I've never understood how having so many teams remains fun for so many owners. 3 at a time is my limit, and even that is too much for me to fully enjoy. I prefer to slowly scroll through the play by play before seeing the final result. That gets too time consuming with more than a couple teams. I'm glad others do like having a lot of teams, otherwise it would take even longer to fill new leagues or replace owners.
Re: tanking, my first attempt at a progressive league bases draft order on how many more games you manage to win than the corresponding franchise did in real-life. That has turned out to be a lot of fun for me, as you can get a race for the top picks, in addition to the pennant races. Playoff team are ineligible for high picks, so the only potential for tanking would be if someone tries to narrowly miss the playoffs in order to get a high pick.