He has no drawbacks. You can't kite him, he can point and click jump on you, then knock you up, then slow you, all back to back, no way to counter him. His ult makes him too tanky for too long. He can tower dive all day long and rack up kills.
I would say he has a very strong early, but it's definitely not like he has 'no drawbacks'. If he falls behind early, he's going to be useless.
If you check https://champion.gg/champion/xinzhao/Jungle? and the 'win rate by game length', you can definitely see he falls off late.
might be one of the most balanced champions in the game actually.
Think about it, he is a CC bot, super strong ganker, with 2 slows and a knock up, but he loses to Vi, Jax, Udyr, WW, any juggernaut, Yasuo, Trynda, Kled early and a lot of assassins past a point.
He is built around having a strong early game, snowballing his lanes or falling behind and being easily outscaled by so many champions.
Late game is so hard to teamfight with him, you have to flank and E-R at the right time to split a fight, or you die for free.
