Personally, I do feel there are a lot of teams that are SO5 and should probably be S5. I thought SO5 was primarily for smaller-ish gyms to compete at level 5 and eventually build a nice S5 team. And seeing super-gyms compete in SO5 with complete perfection and with kids you know have doubles(cough) and have competed level 5 for years(cough) can probably be frustrating for a true SO5 team with few level 5 cheerleaders to select from. But, it is what it is, and to compete in 'any' level 5 you are just going to be up against amazing teams, whether anyone thinks they belong in another division or not. I think it is a fun division to watch!
This is my point exactly with the USASF divisions. Every time we come up with a division for smaller gyms to be competitive, larger gyms always fill a team with it. Same happened with 4.2, senior open 5, and the old Senior Open divisions with 18 and younger. The spirit of these divisions come from smaller gyms trying to be competitive but they get filled with larger gyms who pull in tons of cross competitors and it ends up being some power house division. Until the USASF realizes that small gym divisions are needed, then we will always have divisions that are impacted with these powerhouse teams.