Game-lore

I've written about World of Warcraft and its lore for a very long time now. And one of the discussions that pops up from time to time is the idea that gameplay trumps lore. Why can't humans talk to forsaken, when all forsaken have memories of being human? Gameplay trumps lore - allowing forsaken to speak to Alliance players caused too many problems in PvP. Why did the Alliance allow the Horde to continue to exist after the Siege of Orgrimmar without extracting heavy concessions? Because the story has to accommodate both factions - it may not make a lot of sense for the Alliance and Horde to come out of that moment coexisting, but the game has players on both sides who don't want their faction dismantled.