Not broken. He's not even really a zoning character. He falls in line with mid range characters like Hal Jordan, cyborg, deathstroke, and ares. Frost, lex, raven are way more zone.
Hes actually way underpowered imo. His combos are limited, and his special ability sucks. His ult is pretty standard around 34%, with the highest being 41% iirc in wonder woman and flash. Supes is 38. These were against joker though when I was testing last night.
he is powerful as balls in the iOS game, I wouldn't be too surprised if people start crying OP after the release.
Obviously the game isn't out yet, but from playing the 3 different types of characters in the demo extensively, it seems like the devs did a fantastic job in balancing the strengths and weaknesses of each "weight class"