I just found and picked this up on Steam. While it is no SC competitor, people here might like it for team combat practice as SC right now is a bit of a slog to get into the action. It is kind of like Battlefront, with various scenarios, and has ship battles, drop ships, ship boarding, squad based infantry, and an overall team command system. It can be play SP/co-op with/against bots, I think up to 32 players a side, it has loads of options.
Only downside is third person flight view and I think no HOTAS support.
It is a lot deeper than it first appears.