If they writers go all cliche' on us then the new aliens are going to be worse enemies and the humans and bad skitters will have to join forces to defeat the new menace. If they don't go cliche' on us then it's anybody's game. Maybe they are good, but with a caveat? Maybe bad but focusing their attention on the skitters? Maybe they are just a distraction just to get us to watch season 3. Seeing how this show keeps trailing off from the obvious development I won't put it past them.
I can see it now. The new aliens are only on for one episode as they give some speech about how the universe works then leaves. Or they are actually a travelling circus and came to get our resources a'la crooked carnie games. Or the big alien starts quoting from Rambo movies but gets blown up using his own makeshift explosive arrows. The falling skies the limit here folks.