I have to be honest, I'm not super big on the Galaxy deploying to become a forward base, complete with turrets and such. What I am big on is the concept of players being able to set up and configure a Foward Base, or "Supply Base" using different support components and vehicles. As such;
Galaxy - Infantry and MAX spawn.
Sunderer - Command center with resupply points, weapon points and a shield dome or interlink like detection system.
Lodestar - Vehicle spawn.
Galaxies don't need equipment terminals, as you will be able to spawn in as any class. If you want to have resupply or rearm available, make sure you have the Sunderer HQ set up as well. Same for the Lodestar. You can spawn a vehicle, but you will need a Sunderer to resupply ammo if you have no other source. They all have a function and a limitation that creates a dependency.
Then you have your engineers who can build MANA Turrets and other defensive measures. Instead of having a single vehicle, like a Galaxy that pops open complete with turrets and such, a good Supply Base could be set up and defended by a squad. The engineers would also hang around to repair vehicles as they return from combat.
For me, this is a far more interesting way to set up a forward base. It's more open ended and it would be up to the players to decide how they would want to configure it. They could mix and match the vehicles in any number of ways and put them in close clusters or spread them out. It could be set up fairly quick by a coordinated squad and would fill the role of a forward base that could supply an assault. It's a powerful tool on one hand because as long as you can maintain the set up, you have a closer supply of vehicles and infantry. It also has it's weakness, in that the deployed vehicles can be destroyed by attacks, especially incoming enemy air. Again, it's all in the players' hands to defend and utilize it.
To simplify, I'm saying that we could have forward bases without having the galaxy be an all-in-one unit. Tailor each support vehicle to their role and use them to build the base.
*EDIT*
This is an extremely crude example of how something like this could look on the battlefield.