Do you think UI might fight kaneki in the future ? Do you think UI could live to his hype in battle ?
Oh, definitely. Ui’s conflict with Kaneki is something that has been building for a long time.
Spurred on mostly by the combined fear and jealousy he felt towards Haise, for being Arima’s favorite and also for being a person who could turn into an out of control ghoul at any time, that as canon has shown us at those times only Arima could stop him.
This is further complicated by the recent revelation that Ui actually does regret the way that he treated Sasaki. Before this point Ui only ever saw Sasaki as somebody dangerous who was going to get promoted and surpass him, but after this point he realizes that all this time Sasaki was just trying to fill the distance between them that Ui himself created because of his complicated feelings towards Sasaki.
As to whether or not Ui could stand a chance against him, he definitely could. Of all the characters in the manga who could threaten Kaneki after Kaneki literally made a point of killing the strongest character in the manga Arima, I can only realistically see the two special classes who have been built up as equivalent strengths to Arima posing a threat to him (that being Juuzou and Ui, the next reaper and the hope of the Arima squad respectively). Canon also backs this up, of all the veteran special classes the only character able to hold Owl off for a few minutes before Arima came, and live was Ui Koori.
In the Rueshima arc we see him effortlessly holding off Tsukiyama, Naki, and Irimi all at once without breaking a sweat, and also while picking off other ghouls that are running away.
All of the other characters were beaten and exhausted by this point, and even had their quinques broken but Ui defended himself and kept attacking relentlessly without breaking a sweat until the other ghouls basically just fleed. I do believe he has the physical capability to be a threat to Haise. The question is though, if he mentally would be able to fight with as much confidence as he did beforehand.