As far as potential solutions to the server capacity, the queue isn't exactly a bad idea but it really doesn't solve anything. Yeah, you won't have to spam the login button anymore and can just wait your turn, but the wait still exists.
My thought, is why not do servers similar to how Runescape does theirs? They have over 100 servers that each can hold 2k people. I know that's extreme for this mmo, but rather than trying to beef up the server capacity for one server, why not add a second one for people to log in to? And have social things such as pm's be cross-server so we can still keep in touch with our friends. In the end, I've never tried to host a server so I wouldn't know which would be the cheaper way to go, but it makes sense to me. We could just add 1 more server with a max capacity of like... 500 or 1000 just to accomodate for the extra people playing lately, and when that's not enough, make it equal to the first server. And as the community grows, just keep adding servers 1 by 1 so everyone can play.