I appreciate all your feedback! I didn't think too much about her feelings towards the mech, but I could definitely see her having an attachment to it as she's also part of one of the few squadrons that operates that type specifically.
Thinking a bit more about different playable mecs, I'm probably not going to do that since I think it'd be hard to get them all to feel unique and interesting, especially with having changeable weapons already. In the unlikely event that I do end up going that route though, there most likely won't be any unique parts to unlock for each one since doing it for all of them would be a ton of work and probably not worth it.