Will have more light to shed when bruinsfan911 and I finish updating the world rankings, but All the Way Mae and 7Mantle7 have a lot of openings (9 each), as does Curt Flood (5), and none of them are exactly competitive leagues.
As I'm cataloging worlds, on average there are 3 teams in 4 seasons that lose 110+, in Curt Flood there have been 15 teams! On the flip side, the worlds have averaged 4 teams winning 110+, but they've had 12 in the last 4 seasons. That explains why they have the largest (by a large margin) of run differential between the top 3 teams and the bottom 3. Nearly half the owners in the league also miss their division by more than 25 games - a World record 48 times, the world average is 32.
All the Way Mae has seen 34 teams turn over in 4 seasons, there's 32 owners in a given season (128 over the course of 4 seasons); that's more than a 25% turnover rate.
As someone who blogs for a world, I'd absolutely hate if they merged Cobbfather. I've done extensive backlogging of their history to cover it within the blog, not only for comps for fun to look back at records. So I completely understand being attached to your league for some of those members.