this is a very big issue, most of the servers are dead… i think its because most people moved to the higher pop servers (myself included)
Blizzard has slowly increased the server caps and each time they increase it more and more people flood to illidan and area 52, those two servers are probably 90% of the playerbase at this point, if not more.
I came from a server where you could /who and see 25 ppl online during peak times… illidan has thousands online every second of every hour.
in war within youll be able to join a guild regardless of which server you are on and right now you can trade with everyone. i think the goal is to combined everything here soon but who knows if it will take 1 expansion or 2 before it happens.