Xin top probably will never be meta because believe it or not his level 1 is so disgustingly awful that he loses lane priority the second he steps in lane.
He also has an incredibly weak form of sustain that makes him susceptible to poke heavy champions and his kit essentially forces him to all in every time he wants to execute any sort of meaningful trade.
In jungle he can duel well mostly due to the fact that he's level 3 or so and hasn't been pre-poked to hell and has either an advantage or at least equal XP amount to the enemy jungler he is about to face.
Go watch xin zhao step into lane level 1 against darius or pantheon or hell even something like malphite and watch how he loses the lane priority before the first wave even dies.
Also, xin zhao's waveclear is HORRENDOUSLY bad. He can get by in jungle because a lot of camps consist of one giant monster that you can focus down and then usually whatever is left if there is anything left is lousy. Waveclearing minions is totally different and champions that have excellent single target dps like xin can suffer heavily trying to waveclear minion waves without a tiamat.
In fact, I bet jayce is probably the most insane xin zhao counter. Anytime xin tries to use his one gap closer he'll get smacked back and poked to death. Gnar probably fucks him hard too. Darius just establishes too much of a priority at level 1 for xin zhao to recover from. Pantheon does what darius would be doing but in a more reliable way. Riven the same thing as the former two mentioned champions. etc. etc.
If you're not convinced, xin top literally has such a small sample size that op.gg can't even pick it up
http://na.op.gg/champion/xinzhao/statistics/jungle
It just reads as 100% jungle pick for xin zhao. If there is a xin top meta, it sure as hell isn't here yet.