WF has always been limited. It’s always taken enormous resources to do a WF. Pretty much the entire reason these guilds exist is to do WF.
They play for keep in the WF race, and, when it’s done, win or lose, they then spend the rest of the raid tier building themselves up so they can hit it again. Whether thats making gold, crafting stuff, running mythics endlessly to gear up then entire 20 (30? 40?) man team in full mythic gear so that they can start the next wave with the finest gear available. The gear multiple toons, multiple specs, they freely swap players/classes/specs out from boss to boss, and they all need to be top tiered geared. Because who knows, does an Affliction Warlock offer up 1% more DPS than a Demo or Destro? After the patch releases? For boss #3? This is the stuff they figure out and have to be ready for. So, if your Warlock isn’t geared out for all 3 specs, with the best secondary rolls possible, then you’re not ready.
Once that’s done, they invade the PTR and game out all of the mechanics to find the edge. These guys wipe 100’s of times.
WF is not a 2 week thing. It’s practically a full time chore for these groups.
And it’s open to anyone willing to put in the effort to do this, just know – it’s a LOT of effort.
So, anyway feel free to start your WF guild and get it ready for 10.0.