If you haven’t seen it yet, you are in for a treat!
I don't usually go for wholesale slaughter to clean the slates at the end of a season (and at the end of a contract), however, it redeemed itself on three bits:
First, okay, they did a good job with it storywise. Second, it wasn't a cheap cliffhanger to see who lives or dies while they negotiate contracts. Third, you got to see some of the abilities that the folks we're familiar with are getting.
Interestingly enough, the two main characters (and as important as everyone else is, they are still the main characters) didn't get infected and won't get abilities. At least, not yet.
One mistake in the episode, no one thought of getting Jordan to help Danny, even before many of them knew that Jordan was missing -- or even if they did know he was missing, it's still something to muse over.
I thought they were done with Isabel last year. They used her effectively this year (except for that one incident I mentioned, but why harp).
The city council thing seemed to fall off the map along with the Concentration Camp thing. (Along in Maia's vision when she was being carried off, her body was a little more mature than it is now, so they have a couple of seasons to work on that. But I hope that they don't drop it entirely.)
The downside to the series is that I don't want a year to lapse in the 4400-verse between this ep and the next, but there's only so much you can do with Maia getting older.