We’re aware of a bug where loading screens can sometimes take 2+ minutes to complete; more often after playing in WvW for a while than elsewhere in GW2. We’re working on a fix in such a way that it can be selectively tested on Live, since it affects a vital area of GW2 behavior (loading screen timing), and is rare/difficult to reproduce in a testing environment.
In the meantime, if there aren’t queues in the maps you’re playing in, there’s a possible work-around. Switching maps— either by exiting WvW or just moving to a different WvW map momentarily— appears to get your client “unstuck” from the long loading screen behavior.