More important for Cleveland might be that Thomas will likely work well with Kevin Love.
While the Cavs have tended to do well with Kevin and Kyrie on the floor (after all, Lebron has been on the floor most of that time), they've done notably better with Kevin on and Kyrie off.
And it always seemed there was some sort of tension there.
Thomas and Love both know each other from being roomies during AAU days and are supposedly good friends.
As for the specific question, I don't really see any reason to think that Thomas won't function well with Lebron unless his hip truly is a problem.
If Thomas' hip ends up fully healed and he resumes his prior form, then the Cavs lineup looks to be very, very dangerous and could be difficult to get through. Not only will they have arguable a similarly strong starting 5 as last year (just replacing KI with IT), they will have a stronger bench with Crowder a likely 6th man. He solves some key problems for them in that area by being a better defender than Korver and a better shooter than Shumpert.