I love how the season finale mimicked the season finale for season one, with Diana pointing a gun at a guy and going to extreme measures to save her daughter like Tom did for Kyle. Brilliant, I think. I like her even more now.
It's interesting that the powers have been supressed until now. Next season will see nigh all 4400 gaining powers. I guess that's where this war comes in. I'm still not sure what kind of war this is going to be, who will start it, and whatnot. It sounds somewhat like X-Men's mutants, with the government trying to control them, them being shunned by society, etc. I'm curious just how far this will go.
Richard seemed to have some kind of precognative abilities in the first(?) episode of the season. Now, he's got some telekinetic abilities. Shawn has both the power to heal and harm. I'm wondering if some of the 4400 (or even most of them) will have multiple abilities, especially now that the supressant is gone.
Collier's back! I'm not surprised, but its good to see. Special power: immortality.

He's even more a messiah figure now, what with the dying and coming back thing. Will he want to take the Center back from Shawn or will he have some new goals? I'm sure Shawn will want to wash his hands of the responsibility, but will he be able to?
Isabelle! She seems even more knowlegable than Maia. And, now she's grown up. Why now, though? She wasn't on suppressants. I guess she decided that now's the time. She seems to have some agenda, and she doesn't seem to be... erm... "good." Especially after what happened with Lily's daughter. I did have a theory that Isabelle wasn't the one doing those things, and it was actually Lily suconciously, and I'm not quite willing to let go of that yet. Luckily, we should find out early in next season.
What about Kyle? He's seemingly no longer controlled, so he's pretty normal. Will he go to jail? Will Diana and Marco get together? Were they really taken from the future, or is it some kind of ploy? Is it going the way whoever is behind this wants, or has their mucking with the abilities with suppressants messed it up?
I love the show.