Yes, fixing that cred glitch would be nice, but certainly not a priority because it does not affect gameplay.
I only play on 2-D so i wouldn't know about the other servers not working. I've already expressed my dislike for the excess amount of servers there are. I understand people need euro, and want classic, but the other servers are wasted space imo. I suppose there's probably an underlying reason for just keeping them all; most likely because they're already paid for.
The only other suggestion i have is to make all colors available to everyone. I don't see why this would be an issue.
Also, make the Christmas wreaths, candy canes, and valentine heart spinners purchasable. Or at least make a day where we can log on and get them again..
Edit: Another thing i thought of. It would be extremely dope to do featured maps again. Get rid of all current featured maps (archive them) and start featuring maps from people who actually still play this game!