I'm sure some people enjoy the vanilla experience bu yeah a lot of people will be like "oh right, it was like that", and after a few times of that, they'll just log the fuck off and bitch about getting BC or WotLK instead. Which honestly would be a lot better.
Shit like farming Black Lotus for hours for your flasks for raids, flight paths to Tanaris/Silithus, gold taking forever so you were stuck with the normal mount for a while unless you got super lucky on that 1h sword epic random drop or playing the AH, keying like all of it with Naxx actually being the least annoying in my memory but probably because it released so late, the AQ event fucking nonsense, the horde/alliance "balance" or fuck your fear wards/threat/mana regen, have some more damage instead. Click the FUCKING PORTAL MOTHERFUCKERS STOP RUNNING AFTER THE ONE ROGUE AND GODDAMNIT NOW HERE'S SOME ALLIANCE RAIDING GUILD WE HAVE TO FIGHT AGAIN AND OH LOOK AT THAT RAID NIGHT IS OVER. 40man raids, as a whole. 7mins to runback to Nef's room after every wipe. Decursing(although I'm sure someone will remod decursive again so that should be fine). 5mins blessings that require a reagent to cast. Here let me open trade with 20people for soulstones and healthstones, oh and btw I need to run out and get more soulshards brb in 10mins. Tranq Shot Used, RETARDEDHUNTER420 next... a few seconds later tank dies cause no tranq shot. "Eh guys I'll be afk for the next 2hours in Kargath, making drinks/food for the raid, leave a tell if you need something"
And all that for what, doing some old ass raids with outdated mechanics that'll be a fuckton easier because of better mods and being used to way harder shit. Meh no thanks, but eh some people like playing emulated servers so surely there's some demand.