Moved the thread to a more general discussion arena.
The Following is a personal element rather than as a mod.
If I may flip that on its head as a question to you, if an elite player was not enjoying a league and decided to move to a new one, would you feel it would be fair to both that player and those in a lower tier if the level 30 suddenly turned up in pro or rookie?
It would most likely overpower those in that tier with better drivers and technology and prevent them from gaining access to elite. As it’s likely that there will be new joiners every season, there’s a good chance promotion spots would be blocked off quite a lot. Especially in 2 car leagues where there are only 2 promotion spots.