Rotating OU out would likely make a group of players skipping PRO for a month, including me myself I would say.
People props the seperate queue for 2 tier at the same time, although I would actually prefer this more, yet running both tier in PRO would likely change the ladder system as well as monthly tour. Considering if top players from UU ladders do get rewards and participating in tourney then you should not expect UU to be any fun. It would just be as tryhard as OU tier, a certain group of pokemon would be dominant, especially since some answer to certain UU pokemon are now banned because of OU, so no, you would be seeing the same pokemon again and again, nothing new. Well this is where "the council" put in their works and make these mon into UUBL. But as of "PRO council" state rn I don't actually think it's possible to start this idea yet. maybe in 3 months time it would be different.
There are many others problem I would like to call out, but for now
in short : NO