As I am sure many suggestions have been, this has probably been suggested before.
Too many times I or someone else will receive a quest that may prove slightly difficult (or impossible/requires) multiple people. But when we search, there are no people available or willing to assist!
My suggestion is to create a few more realms, each dedicated to a specific world, where the large majority of players would play in to assist or receive assistance with ease.
Perhaps you have a favorite world you like to visit often, but there's never anybody online who shares your interest? Well, head over to a World Specific Realm and finds loads of people who could share your interest!
Not to mention it could certainly act as a gateway to new friendships between players as they play together and help each other out.