I actually agree and disagree at the same time. Xin was already a really strong champ, but he fell off late game. The rework shifted things around and the passive is strong for late game, with that ult. Atm I'd rate him as a top champion, but I don't know about overpowered. Possibly, with about 5 games with him, and 1 against one. I can't tell yet. However I have noticed that something fishy happens with TTS at max rank. I had some CDR but the tooltip said 4 seconds CD but a 6 second CD would happen. If this is an unintended bug and they fix it, then xin would definitely be up for a nerf. At the moment, at most he would need some slight number adjustments.