I don't game at all anymore, but I was in the original WoW beta -> off and on until the end of MoP. The devs had an identity crisis from mid Wotlk onwards. They didn't know if they wanted to be an MMO or what I'm going to call a "lobby" game where the world was scenery for raid content which was developed for way too many demographics.
By the time MoP was over, the problem Cata suffered from where there was no reason to actually explore the world was back. This happened despite the devs putting a hefty amount of incentives outside the Shrines. However, the reason it happened was because the game had slowly removed the RPG elements in an attempt to make aspects of the game more accessible to casual players (casual == can't commit large amounts of time to the game). It's been debated to death whether this is what really did the game in or if it was age or if it was sometimes trying to walk-back the casual-access (see tier 11).
Only speaking for myself here: I remember the days of Vanilla WoW as the best I'd ever had in the life of the series. Back then Azeroth felt like an actual world, not a collection of zones. Some areas had special quests, for special items which didn't seem to have a purpose... but later, you'd discover ON YOUR OWN that certain items had very cool functionality. I remember farming blasted land boars for our first Patchwerk kills in Naxxramas. I remember clearing BRD for super specific purposes and leaving half the dungeon alive -> even doing so to zone into MC. I bitched up a storm at the time that we weren't allowed to just zone into MC... in retrospect I enjoyed it more than I was willing to admit, having all of our guild online at the same time and not being in a stressful progression environment (eventually clearing trash replaced this).
Crossroads <-> ashenvale PvP? When the game was fresh and everyone's gear was ass, and no one knew how to spec it always felt like a fair fight. No one cared about honor kills, people used general chat for things other than chuck norris jokes. You got to explore an area that you most likely didn't see leveling up (Ashenvale for horde, Barrens for Alliance). Once again, I was induced to experience the world, I wasn't incentivized for daily badges, a quest where I follow the waypoints and kill or click crap; Everyone had an excuse to meet new people.
By the time I had sold my account, if I wanted to do a dungeon, I clicked on my UI and stood there. If I wanted to run a CM, I scheduled it w/friends in advance, if I wanted to PvP I clicked in my UI, if I wanted to make gold, I clicked my auction flipping add-on (I actually had to move my character to the auction NPC!). Raid time? In MoP the only raid that had a commute was ToT, everything else took 10 seconds to fly too. Raiding itself? I retired form the hardcore scene when you had to raid every waking hour of release to compete, I had all the strategies in advance, it was a matter of getting the guild to learn the strat -> farm the gear to beat the checks. Being entirely honest, I hadn't been having fun for a long time, the social bonds are what kept me there; but it could have been more, the game felt corporate, there were no risks with new content, it was more of the same. In trying to please everyone, the pleased no one.
What would make me give it another shot if I could find the time to play? Blizzard leaving Activision, going private, hiring a 100% new dev team and starting from scratch from an idea perspective. It doesn't need to be Vanilla/TBC like at all, it just needs to have it's own identity, and not implicitly apologize for not catering to everyone with every bit of new content (casual, hardcore, or in-between).
I played on a pvp server since vanilla and this reads like madness to me. Raids were a mess of pre-grinding and too large groups, most classes had specs that were useless shitty or super nonfun to play, you were lalways doing the same instances.
The only thing vanilla had against BC and Wrath was the fact that the world was small and non-splintered so you had Gankfests like Nesi camp. All the actual gameplay and pve content got better later. Sure as a druid I could gank people in badlands until they'd cry and ragequit but what if I wanted to do dps in a raid or heaven forbid even tank? Or hey, remember when you needed to have 4 warrior tanks in to raid Naxx?
I can only assume people want vanilla back because they miss being 10 years younger than now.
- On raiding, assuming you were on the "cusp" of raiding given you were in Naxx, was it really more enjoyable trying to replicate videos/strats than figuring out a boss yourself (even if the mechanics were lame by today's standards?)
- Pre-grinding before raids is still a thing, anything with a DPS check => gear check => 95% of the raiding population doesn't play their class @ max efficiency, so you are grinding, just in another way (raid lockouts)
- I'd take being ganked or harassed any-day of the week over the "world content" we got in the form of repetitive boring daily quests.
- Bear druids with the green spell-hit rings works just as well as tanks for the 4 horesmen fight. It was actually easier because the tanks needed 4 piece T3 for the spell-hit and that required gimping the best DPS (rogues)... assuming you ignore the fights they can't help on cause melee. More interestingly, Blizzard was willing to make fights like this back then. Nowadays they'd get screamed at by the "not fair side" -> cave -> then the "stop watering down the game side" would whine, no one wins because the fight is lame and the people who are normally in the "not fair side" usually bitch about content not coming out fast enough.
Missing Vanilla isn't just nostalgia, Vanilla was a different game for better or worse and by the time Wotlk was over, most of what made it different was gone and we don't know how it could have turned out had the devs stayed the course. Of course at the time I cheered most of the changes, but reflecting back I can honestly say I admired the game more in it's earlier state than what it's become.