Hola, I've gone through a few Hex games on the PBE and I'll definitely say duo jungle is a bad idea. Not enough jungle to go around unless one is a dedicated counter-jungler.
AoE cc and Teleport are amazing, in my experience lane roaming happened a hell of a lot so sudden reinforcements and ganks really work.
Global or seim-global ults like Ziggs, Jinx, TF, Shen and Pantheon do a lot of work.
Essentially there will be two general outcomes. One lane will win/lose horribly and the game will be over quick or it will be a 50+ min game with constant 2v2's and 3v3 erupting all over the map. Honestly the pace felt very similar to dominion, with constant fights happening everywhere and me always wondering if I should help of push another lane.
Oh and also, bad news for divers like Renekton and Vi, if they're grouping you will be eaten alive. You may still initiate well and win it for your team, but you will most likely die in the process :P Have fun!