Now, if someone out there wants to steal this, some points of advice.
1) Have more than one season ending scheme/job that takes different combinations, on the offhand chance it gets renewed, so you need another setup (or different folks with different powers?)
2) Never have the last episode of a season cliffhang to the next. Have the start of the new season (if reusing the previous folks) finding our heroes wondering why they still have these powers.
3) Have part of the contract with the network be that if it's cancelled, you're allowed to release your arc notes/plans to the public.
It really seemed 4400 was going that way, but it never really did.