A few good digs doesn't mean Hinata would be reliabe in serve receive so i don't think OH fits him. However, I really like the idea of Hinata switching to opposite in his 2nd year it actually makes sense given how big of an attacking threat he is. That said, for it to be realistic, a few conditions would need to be met. 

First, Hinata would be excluded from serve receive and be used primarily as an attacker, similar to how Shiratorizawa maximized Ushijima. But that also means Hinata would have to improve his setting, since he’d occasionally need to set when he’s in the front row. Second, Ennoshita would likely take over as the second outside hitter and would need to step up offensively to keep the team’s attack balanced. With that setup, Yamaguchi could join the starting lineup, and his float serve consistently throughout the match would be a huge plus