Considering that many of the servers meld in groups when there isn't enough people in a zone, I don't see much cause for looking for a balanced server these days. But then I'm not into PVP anyway. The Combined Arygos-Llane servers are likely balanced now. Arygos was an alliance PVE server when I joined it during TBC. Though there were still battles between Southshore and Tarren Mill from time to time, as well as sometimes a Horde raid on Goldshire or Westfall. The eventual response would be sacking Undercity, and then sometimes Orgrimmar, if everyone got in the right zepplin. Otherwise it end because Stranglethorn's base guards had massive knockback when you try to come off the zepplin. There is/was a plan for a 100 vs 100 battleground for the Tarren Mill vs Southshore wars. An effort so simulate the old days plus maybe a but of old AV as well.