From what I've seen, not a whole lot has changed on 3s...
You still want 2 solos and a jungler, you still want as much CC as possible, you still want bursters/duelists with AoE. So...the "best" team comps are still the same...
If anything, less champions are viable in 3s now because who wants a support in a game without wards?
The only thing I see as changed is that flash champions can't wall hop as much and there isn't a constant battle for pink ward control at Red buff because there are no more wards and there isn't a red buff. The dragon moved a little bit north, got fatter, and grew some extra legs, and all those OP buffs in the north are gone.
As a 3s jungler, I have to say that things have really been watered down. There is little risk in jungling any more, its much easier, and with no wards ganking is really easy...