The issue with TR and AoC was not that WoW is such a monster hit, but that these games were not up to the standard people now expect from MMORPGS nowadays.
WAR is suffering the same issue, people are stopping subscribing in droves because of the poor PVE in the game. Relying on a good PVP system to cover up the fact that the game itself is quite poor is not working, the only players left playing are those committed to 100% PVP with is a tiny proportion of the MMORPG market and quite a fickle population.
If WAR's PVE had been half as fun as the PVP I'm sure it would have been an enormous success. Providing poor quality PVE does not improve the PVP in the game, it leads to falling subs and worse PVP.
The lessons that need to be learned are if you want a successful MMORPG, don't listen to the bean counters about releasing an unfinished/poor quality game, the playerbase will not stand for it.