Actually this question sent my mind spinning:
1.) Khabib came from the ring and adapted to the cage so much the wall became his number one tool, utilizing it better and in ways no one had before.
2.) He looked less dominant in his early fights for a variety of reasons obviously, but without the cage he becomes much less dominant imho. Obviously everything here is hypothetical but in his current state he is almost ordinary without the cage. Of course, his game would adapt to a ring too, as my previous point shows he will get good using whatever rules to his advantage. But without the fence with the same game he had in the UFC when he retired? Looks very beatable, still awesome and well rounded, but beatable for sure.
Good Q TS.