Nothing.
Deep inside, most people that've been playing since Vanilla (or even TBC) know that what they want will never return. You want the unobtainable, a recreation of those nostalgic memories. But if you think back about what made WoW so good, it wasn't just the fact the game was good. It was a combination of many, many things.
The internet was really moving forward back in those days. It was starting to become much bigger and stuff like youtube was taking off. But despite that, I felt like there was still a sense of mystery surrounding the internet. Like, it's so easy to find info about videogames now. Downloading mods/addons is basic stuff, too. I felt like people back then were still discovering stuff. And that's probably why WoW itself felt a lot more mysterious as well. You couldn't just open google and find everything about the game. Barely any addons. Hitting level 60 felt like an achievement itself. Most of us were younger too. Which also meant that most of us weren't as tech savvy as we are now. It had a certain charm to it. I still remember how Azeroth was an unknown place to me. I'd never know where I'd end up next. The way you had to do dungeons was much more personal and would often end up with new friendships once you finished one. I guess that's one of the biggest disappointments of todays technology. Everyone wants faster access (understandable) so a lot of group efforts in multiplayer-focused games have become less personal, as can be seen with LFG. I just feel like you can't recreate a lot of those personal experiences from way back in 2006.
But I'm drifting away from my main point. Which is that I feel like the game was really a product of its time. It was the right game at the right moment. A lot of those good memories I have simply wouldn't work today. If I really think about it, a lot of my most cherished moments are some of the most awful gameplay-related moments. Like the trouble you'd go through of managing a 40 man raid. How one small mistake would ruin an entire boss fight. But the feeling we all had when we finally defeated that one boss... it was the best.
But I think what I really miss is how social this game used to be. How much it used to rely on that aspect. How everything used to be limited to one server. It was an entirely different experience. I used to have real enemies in PvP. Not just randoms from another server I probably won't remember. I used to play dungeons with people I knew. People I'd keep talking to, even after the dungeon. Not just randoms from another server who don't say anything except for "tank gogogogogo." And yet I can't blame Blizzard for introducing battlegroups and LFG. Even I can't deny how the one server limit was ruining both PvE and PvP on less active servers. From a gameplay standpoint, I understand them. But that doesn't change the fact most of my favourite moments are from before Cataclysm. Wrath of The Lich King was probably the last expansion I really enjoyed. And a great one too.
But even if Blizzard made a 1:1 copy of Vanilla today, it wouldn't work. It's not just the game that has changed. It's everything. This game is more than 10 years old. Technology has changed. The world has changed. But perhaps the most important thing is that most of us have changed a lot, too.
Great post, i agree 100%