I wish there was a way to play online when testing new classes without being punished for it, maybe a dummy account that has no stats what so ever or something as it is quite annoying with all stats dropping if you have no idea what to do. I dropped from 4.01 to 3.02 in 4 games using support as I don't have a clue how to use it and there is no way of getting good without practise. And no blitz is not good for testing classes at all.
I think it would be possible to set up a server without stats via command line. Haven't seen a server like that yet though. It would be nice to have a few to test new classes, that's true.
Unranked servers would be cool and all, but who cares? If you are having fun, what does it matter if you have a 5.9 next to a star vs a 3.8 next to a star? I play all the classes now, I have more fun because assault isn't that fun anymore, and I don't care about a silly little number next to a star. I have math classes to care about numbers in.
There are so many dumb ways of losing star rating that I just don't care anymore Waiting on an empty server for people to join will lose you stars Playing a 1v1 or 2v2 while a server is slowly filling up will probably lose you stars, even if you win by a large margin
Dummy accounts are not a good idea. But why not just make one rating for each class for each player instead of a single, global one? A rating of 5.0 doesn't mean you can play any class equally good.
