>>538023985
This is bullshit obviously. All Marines can change equipment as need, they are fucking marines trained in a variety of weapons, in an addition to being Space Knights. Straban could squeeze into Phobos armor and go Vanguard and Decimus become a Sniper if need be. It's mentioned few times during this game story even.
All that is needed is an option to select your Character separately from Class.

The actual issue is in some of classes abilities not being designed around stacking of them. But honestly it's only really a problem with a Banner and an Auspex scan. And a meager one at that. They fucked up conceptually by forcing class restrictions on a design stage, but if they patched in class stacking in some update closer to release then they would have balanced it all until now to a reasonable state already.