Sorry, long post.
Please all raise your hands who have never dabbled in User Experience Design or actually never worked as a designer or did a design study at all...
Tbh they stand out like soor thumbs in this thread and all across the board. Please don't take this as an insult, but it's true.
Sensory cues and categorization are incredibly important to good designs, as is functional and practical design.
If every unit looked like a Sunderer, including the ATVs, I'm pretty damn sure it'd be perceived incredibly important. Just because half of you are not interested in a good design and content with an half-baked design, whether or not it does its job and whether or not it fits your definition of "good (enough)", doesn't mean it's actually good design.
Those people that say "but you can make anything do everything in a game".
Yes, you can make a stick magically fire nukes in a game. You can make tanks fly and have afterburners without them being visible (some games probably did that too). Great! Who cares what things look like? It's not like immersiveness or user experience has ANYTHING to do with how the user experiences the game, right? It's not like visual IFF design is at all interesting for a FPS, right?
Certainly not a MMOFPS where friendly fire is active! It's not like it matters if an immovable object accelerates to the speed of light because it's a
game, right? Who cares if it communicates well what it does and is for and if it's made both believable and functical on more than "look I can fire with it" within the game?
There's loads and loads of reasons why good and believable game unit design is important to the player. Most of you should know why, but I don't blame you if you don't realise it, because you've never really cared to think about it because you just want to have fun and you don't really care for the design details and leave that to others. Fine. And I can definitely imagine you've not had an education in UX-design or ergonomics, hell most designers don't. And my knowledge of ergonomics is also not as optimal as I would like it to be. However, I do understand the importance of it and I can relate to those who don't see the importance of it, because it's not something a lot of educations pay attention to (Aerospace Engineering including, but Industrial Design Engineering does - let's put it this way - I worked with fellow students who could calculate structural frames to milimeter, but could not realise that their protective frame completely blocked a pilot's view and didn't care for incorporating a toilet or 'personal waste' disposal system or any other ergonomical features beyond a chair and a bucket for a kitesurfing, transatlantic boat / plane). People typically don't want to think about things they feel are better left as afterthoughts or 'unimportant'.
However, if something looks like a tank, but is actually supposed to have the tech specs of a buggy or ATV, I'm pretty damn sure this doesn't "FEEL" right to the gamer because it communicates something else entirely! This is the same for changes WITHIN a single unit.
The question is if you ever think about intuitive design yourself, or just in stat balance? Most gamers think in stat balance and some might go as far as saying "okay that hitbox should be a bit bigger and that unit a bit smaller and have more hitpoints". They don't think about the fundamental design of the unit. I've only seen a very few people raise the issue of the Magrider's main gun being very low in relation to the other tanks and having to turn its hull where the others do not.
Most people don't even realise this has tremendous design and gameplay implications even if it's probably the most obvious "error", ie making one TD and two tanks. Why was it done? Because they kept to the old design platform's basics, while changing the role of the driver as they wanted the driver to have the main gun and this was the only logical driver gun within that configuration!
Please people, realise that this unit's platform wasn't fundamentally changed aside from aesthetic appearance, just that the driver's role changed, meaning ONE gun configuration change. Yet the entire unit's role and use were changed! Platform design means everything to roles and the other way around! If you go by a platform and THEN determine a role for it, you're doing it the wrong way around! PS2 is doing this, a lot! They first design a unit, then give it additional functionality that doesn't suit it because of rather arbitrary reasons.
The Galaxy, the Magrider, the Sunderer, I'm sure other units will have the same sort of multi-role problems where they were designed for one thing, then a different role got shoe-horned in.
All this goes for a unit "look and feel" in general, as well as it goes for if its accesspoints and interaction areas are recognisable or not. Take the PS1 AMS: due to its equipment terms being very visible and attracting attention during deploying, you don't need any yellow circle on the ground. You don't really need those either at doors as you can easily identify those accesspoints. However, you do if you want to know in an instant if it's locked or occupied or not (red crossed circle).
If you make the Sunderer to be an AMS, you will need a lot more of these use cues on the ground, because they wouldn't be visible on the Sunderer itself, though probably they'd make people accidentally find it by stumbling onto a "PRESS G NOWZORS" on screen.
This would mean it feels far more like a game. Because the function of the unit is less intuitively integrated into the design of it unit than it could, meaning its use is far less obvious. Using that same example, for a new player learning the game, it's far less obvious that a Sunderer is or can be a spawnpoint if they just see this big APC until they accidentally use it, are told about or otherwise come across it. So of course eventually they will learn it, but if they have to ask or learn from others, then the devs have poorly designed this element of the game as it is not self-explanatory.
By now I suppose you understand we're not talking about basic design 101, but on a somewhat higher level, I hope?
Of course you can make a half-arsed design, put some text next to it, expect people to read that (hah!) or figure someone will eventually figure it out and tell others. Great. Works. Bad designer attitude and bad design, but works. But because it works, one should never strife to improve?
So great. It probably "works". Is it good design? No. Will it feel cheap? Yes, you won't get the impression the makers really put a lot of effort in it - even if they have in the sidegrading - if you only get one basic frame. If people come in from World of Tanks which per unit has a lot less sidegrading, but realise they can only sidegrade two tanks per empire, they'll probably go "okay, uhm... where's the rest?"
If you look at World of Tanks, tanks themselves undergo a couple changes, but the variety of changes that you will be able to make to a single frame are limited. In PS2 per frame the potential of changes will be much greater, yet I wonder if that's actually important as people will go for certain setups and then leave it with that. How many of the gamers tune their cars in racing games after a one or two attempts? I certainly don't care for that, I just want to race. Same for my friends and relatives, only my nephew is interested in tuning his car. The remainder just use the default or put on a scope in CoD (if even that) and call it a day. 80% of the customization options of a single frame are left unused. This is even more true if there's a certain optimum. So once that's reached, there's no point in spending more certs on it. If there were other frames, sure, you'd happily do it for that frame too.
Either way, these changes should be visible on the tanks. But IMO it's questionable if people can still make out these subtle differences, especially if the skins also change from unit to unit making any subtle changes less obvious because people first have to get accustomed to the big skin change.
And gamers will definitely want to know what they're up against to determine their strategy (rather than just if they engage at all which is the case for aircav regarding AA). But yes, even if you're not aircav you'll care.
Again look at World of Tanks as an example. Is it important to know if you're fighting a Tiger H or a Tiger P, a T29, IS or KV-3 from a huge distance? I mean they're all Tier 7 tanks right? How different can they be? Well... A LOT. The T29 has an incredibly strong turret which you can't damage safe on a few tiny spots, but a very weak hull, especially side and rear. The Tiger P and Tiger H have very different weakspots, particularly noticable in frontal section (100mm or 200mm), the IS and KV-3 each have different bouncy areas, different speeds and different engine locations, etc.
If all the hulls would be the same, you'd fight each enemy more or less the same. If each hull
looks the same, but in reality
isn't, that will be very annoying.
So yes, yes it is important. Does it matter if you know what turret or gun they have? Yes of course, but that's not relevant till you're closer. By simply identifying the unit, you know HOW to engage it, because you know its main weaknesses and strengths. Advance knowledge is everything in any even remotely strategic game and PlanetSide is almost a RTS. Pretty much every MMOFPS player in PS1 looks at what weaponry an enemy carries or drives before making decisions.
Instinctive decisions can mean everything between winning and losing.
CAN a turret and gun change on a Lightning for instance be enough to make any stat change obvious? To a degree yes, but it's definitely not the BEST, the ONLY nor a COMPLETE way. It's a somewhat half-arsed way though at least it's a start. However, you can't expect the unit to have wildly different other stats relating to the hull from the other units, while if you created a different platform (hull / frame), you would be able to tweak everything from scratch.
It's just a bit more effort put in than "look, I put a bumpersticker on it that says I'm an AA unit".
But yeah, I don't think that's very good design. :/ It can be
sufficient design as most of you indicate, but I'm not as easily satisfied as the people who say that. As you can tell from this post and the others, I got different, probably higher standards to be met before I call something good.
IMO, a
good game unit design visualises any inherent characteristics of the unit in question in an intuitive manner on ALL levels that are relevant to game play in the slightest. Not on some levels. No compromises if you can avoid it. On ALL levels. For PS2, that means its empire, any functions, entry points, speed, weight, armour, maneuvrability, sound, you name it. If it loans any of the same visual information from an entirely other unit it also means it communicates the same characteristics. Even if they can have very diverse characteristics "because it's a game".
Everything has to be communicated to the players that are using it and those that are competing with it.
But are different guns enough? Take the ES Sunderers from PS1. You could categorize it as a Sunderer APC, but I highly doubt people knew which gun was which till they got in (most people quickly trying to get in to shoot at aircav ended up in the 75mm guns instead of the ES straight fire guns). Even if they were quite distinct. Even if your configuration per empire was fixed. I even doubt that if you put a Vindicator, Leviathan and Juggernaught next to each other in random empire colours and with the name not in sight even if they can see the guns, that people can really differentiate between the TR and NC ones in particular.
TL;DR:
Is it possible to design by just altering guns and turrets? It's possible certainly. But it's not obvious and needs a lot of identification experience, meaning it's not intuitive. At the same time, I'm quite sure people can immediately differentiate between all PS1 buggies, etc. They don't have to squint their eyes and look at the guns: they just know from the basic profile what it is and can do: Between buggies: what empire is it, is it AV, AA or AI. And in relation to other units: is it agile, speedy, less hitpoints, you name it.
All you ever may want to know about an unit seen in ONE single instance.