Hm, so this idea really is going live I see.

To me, we should be placed into squads. As a squad, the players should probably go for mech designs that offset another team member's inherent weaknesses, or rather go for a specific combat role that is made evident by their mech's specifications. Story wise, we could go for the so-called 'homeland' being under attack, though maybe it could be interesting to put the homeland in a dire situation. Perhaps it's been invaded by foreign forces, with armed civilian groups and official military remnants forming the backbone of the resistance movement or something.