Winning tactic by sacrificing your crew!
Not sure if this is a 'exploit' but a way I've found battling ground missions too hard to do... Send your crew ahead and don't respawn till they're dead.
I've noticed quickly that my crew keeps fighting after I'm dead. I've found that I'll send them ahead, lock them in place to a spot. If I die, I wait until they're all dead and let them kill more ground enemies on away missions... I found that this is very helpful when I'm extremely outnumbered. Its not exactly a 'exploit' or 'cheat' but comes in handy when you're very outnumbered. Sacrifice them to save yourself and make it easier to battle the masses on away missions.