Going to play devil's advocate for a minute here.

According to the blue posts, the server issues have largely been caused by DB updates, which are done every time a player creates or leaves a game. This is a big reason why there is a limit on how quickly you can create games.

Currently, there are three shared stash tabs. If we increase that to twenty, then that increases the DB load for every account by seven times. And players with these shared stashes are still going to be creating new games every seventy seconds - not to mile, but to do travincal/meph/pindle/whatever.

I don't really have any evidence that this is what is happening. But if there was a technical reason for not having more shared stash tabs, I think this could be a part of it.