Which version do you subscribe to, regarding the future we see?
1) Alternate timeline, in which John Connor is dead, and not the leader of the resistance, and therefore Kyle, Derek, and Allison are alive?
2) A future in which John Connor isn't the leader of the resistance YET, but will become one?
I'm kind of hoping to subscribe to the 2nd one, given the subtle 'you're going to be famous' from Derek, and the fact that through the entire series we had Future!John obscured from our view, possibly to hide his age from us, so we wouldn't know he was just a few years older than Present!John, and Derek and Kyle seem to be made to look younger than the last we've seen of them... Then again, Derek references celebrating (I think) John's 30th birthday with him, so dunno.
ARGH. You can tell that the finale just blew my mind, and THEN danced among its ruins cackling madly.