Keba is Fous with 2-3" extra inches. Fous has a 7'1" wingspan which is why he plays at the 5. But he is still undersized and not a true 5, the same with Keba.
Does he play there, sure he does. He doesn't have anywhere else to play. But he is an undersized 5 and will be a liability on offense. I'll cheer him on if we have him, but he doesn't fit the mold of players we have.
Atiki didn't see the court for a lot of reasons, but one of them was we didn't need a big who can't pass and has a limited offensive game. That is exactly what Keba is.
It KY wants a Deandre Ayton for some reason, the Keba fits that bill. But nobody knows what KY wants right now, nor the offense he will choose to run in college.