Coming in late to the discussion, but...
I really like the proposed system. It hits most of my concerns about the resources as they stand right now.
What I would suggest, however, is that personal nanites be used for more than just major force multipliers like tanks, C4, etc, and also have minor costs associated with many of the actions that players can do. I don't know what values you're considering, Malorn, but hopefully this gives a reasonable idea:
- Spawning costs something like 15 resources
- Spawning at a Sunderer costs 20, slightly more, to give permanent spawn points a logistics advantage
- Hot dropping costs 50... dropping from the sky is incredibly helpful, so it should have an appropriate cost!
- Reviving a downed player costs 5, substantially better than having them respawn, but makes it burdensome to do so continuously.
- Deploying a MANA turret costs 20, so that Engineers are a bit more mindful of their deployables
- Tanks and aircraft require resources to repair, making them dependent on resources beyond just the initial pull cost. In fact, reducing the pull costs for vehicles in exchange for more action-based costs would make it so that careful pilots and drivers who keep their vehicles alive a long time still need to consider resources.
- I'd love to have rearming vehicles also be resource dependent, but since most forms of re-arm are automatic that's problematic. One solution might be to make the actual FIRING of the vehicle weapons costs resources, which solves most of issues one might have with it, but might be intuitively a little odd. "I have 30 shots in my tank, but I have to spend resources to fire each one? Huh?" Then again, you're already doing that with the infantry consumables, so maybe not a big issue!
- If you want to go a little crazy here, you can also use resource costs as another knob to tune in class and weapon balance. Decimators are just plain better than normal rocket launchers? Fine, but you'll pay 50 resources per shot! Want to make the empire specific heavy weapons fearsome and devastating, as they should be? Great, but spawning with one or switching to the loadout will cost you an additional 50 resources, so you better be careful with that thing! I really, really like the idea of having special, powerful weapons or vehicles who can punch above their weight but sensitive to logistical concerns!
- I suspect I don't need to mention this, but on principle all player resource expenditures should be initiated by THAT player's explicit action, and never by someone else or via an automatic system. That's why I've got the medic paying the cost of the revive above, for instance.
My intent with these suggestions is to emphasize resources as a personal measure of endurance (IE, the supplies that the player is bringing with them into the field, instead of a bank balance back at HQ) and making player actions reflect that. Players attacking enemy territory or defending a base with hampered resource output should need to be thinking about this stuff.
I think making this stuff absolutely critical to moment-to-moment play is the best way to pump up the mechanics you're talking about and make them sing. If players KNOW that resources will have a significant impact on what they can do and how well they'll stand up in a fight, they'll care that a base is being cut off from resupply and resources will become a critical part of play. If you just restrict it to the cost of pulling force multipliers, players will be a bit annoyed by it but it won't really stop them from maintaining a solid infantry defense/attack, which is what wins a lot of battles.
As far as the resource gathering vehicles goes, I really like the idea of a separate ANT vehicle, for the same reason that others have mentioned: easy identification and separate balancing. Shoving it into another Sunderer module would just make that vehicle even MORE difficult to read, and would impair the counter-play to resupply efforts by making it impossible to identify the critical target in a convoy. It'd also make sense to be able to tune the cost, mobility, and defensive capabilities of the ANT separately from everyone's favourite rolling brick.
Malorn mentioned that it's not ideal to have a vehicle that's just a "space truck" with a sharply limited role, and I totally agree. My thoughts are to make it a more general resource support vehicle. If you implement the kind of resource costs for individual actions I'm talking about above, there'll be a very real risk of friendly players running low on resources in the field, especially on the attack. Why not, then, allow the ANT to resupply nanites to players as well as bases with an optional module? Either a triggered AOE resource distribution or deploying a "crate" of some kind would do the trick here. If you do that, then you might also be able to get away with nixing the attacker's ability to resupply from an adjacent base, since they'd now be able to bring in ANTs to fuel their assault, an interesting strategic wrinkle that a savvy defender might be able to exploit!
An alternative module might instead let you spend the ANT's stored power on a defensive barrier for nearby vehicles and infantry to protect them from aircraft and return fire. That way, you can pull ANTs for things other than resupply runs... those same resources can also be applied in different ways, powering powerful special abilities that REQUIRE the ANT to recharge at a resource node. They can be powerful because they're limited by the ability to recharge the ANT as opposed to ammo or HP that can be locally resupplied. There are a lot of interesting tactical and strategic implications of that, and it'd be a very different kind of gameplay!