Leagues

It would be nice to be able transfer (buy and sell) players between teams and maybe guild leagues where your guild is in a group of guilds called, maybe Division 1 or 2 or 3 or Premier and guilds play against each other for points. There could be promotion and demotion of guilds between guild leagues.
The trade market would be a holy mess
There are lots of good reasons spelled out on mutiple occasions why transfers within guilds won't happen.

Guild leagues? Struggling to see why we might need another competition, but I've no objection to it personally.
The benefit of guild league would be a higher likelihood of drawing good competition. I don't mind that part of the idea
You'd get people passing rp on so unless it was a trade without RP involved in the transfer you'd have some potentially very wrong things in the game going on
I was talking the guild league part, not the auction house part.