I thought some of the older, larger servers already had maps that were 1000x1000 instead of 500x500..why wouldn't the WN servers be made 1000x1000x or possibly a larger size to accomodate the extra people?

As for suing them over how they handle things in game, you can't. Evony and all other cash shop based games have a terms of service agreement that you agree to before logging in that clearly states that they are under no obligation to continue their service, and can cancel your account or do anything else they want to it at any time without any reason, so even if you bought coins and your account was deleted without notice the next day, you cannot sue over it.