Instead of trying to use formulas to make things even.. why not use a shaming method. Each team has a count of how many times they did NOT promote..

The game is about pride of winning.. so how proud would they, tankers, be if everyone can see how many times they have tanked..

Additionally; if changing formulas; teams that didn't make it to promotion 1x, 2x but stats above 100% can still be generated in competitions together more frequently, so they can not all win next season's.. Or 2 times not promoted will give all players penalty.. and every time after as well, somewhat like suggested elsewhere..