Relegation can't work with the current mechanic imo. Tanking teams tank to build resources or increase Q or both to be competitive at the current level. Put them down a level and they will gain even more since their players will be, relatively speaking, 1 star better. You might then think penalise those relegated teams, well how would you differentiate between a competitive 8th placed team, a tanker, abandoned team or someone taking a break.
Think how those tanks would look using the current mechanics if they were relegated from Level 13 where they had an even higher level TM+Season's SP rather than a lvl 12 Market + season's SP.
Tanking does serve a purpose. Its not just about seeking an advantage. It maintains population too allowing those 35T players to maintain a presence rather than leaving for somewhere else.
Anyway, decided to fire up the numbers. Here's one of my alt teams draw by Q.
Top 7 teams: 30.1, 29.9, 29.5, 29.1, 28.4, 28.1 & 28.0
Bottom 7: 25.4, 25.4, 25.2, 25.0, 24.6, 24.5, 24.4
Could just be coincidence but again I think the league is composed of 2 weighted groups.