I started playing on Kronos due to nostalgia, there's no doubt about it. I just wanted to see old Azeroth again. But as the above article says, nostalgia isn't what keeps you around. I stayed because I was actually having fun again.
In fact, too much nostalgia is probably a bad thing. I'm pretty sure it's a major reason I haven't really gotten into playing my priest alt. Playing her reminds me way too much of the aspects of my original WoW experience that I can't really recreate: being a student with seemingly endless amounts of free time, having friends that levelled with me the entire time, the fun we had together.
In hindsight I think that recreating my pally instead was definitely a very good choice. Since she never got very far in retail, playing her hasn't so much been an attempt to relive the past as a trip to an alternate universe where I never re-rolled night elf. How would things have gone if I had continued to level as a human paladin? Well, now I can at least find out what the game would have had in store for me...
As I said, levelling has been fun again. Even though old Azeroth isn't new to me anymore, there were many things that I'd forgotten. I love just how "worldly" everything feels. I used to find those quests annoying that send you all over the place, but it just feels more natural now that I've seen the alternative. Sure, in some ways it is annoying when the quest giver in Booty Bay sends you all the way up to Dalaran just to talk to a mage, but it's at least equally nonsensical when everyone and everything needed to solve an issue has been within a one hundred metre radius the entire time but nobody thought of talking to the guy over there or picking up that box from around the corner until you arrived.
The longer-lasting fights out in the world highlight the strengths and weaknesses of different mob types vs. different classes, while the higher mob density and increased danger posed by enemies in general force you to pay attention to your environment. You spend enough time in each zone to learn all its ins and outs and get opportunities to meet people. Professions require work and gaining stats is meaningful. When you get a buff or a new gear piece, you can really feel the difference in power it makes! Everything just flows together to create a great experience.
Imagine my surprise when I found out that some people, even among those who play on private servers, think that Vanilla levelling was crap.
Just one example I saw on YouTube. Click to enlarge and read.
My first reaction the first time I saw someone state this in chat was one of shouting "Blasphemy!", but this was soon replaced by intrigue. If they don't like the levelling, what other reasons do people have to love Vanilla? I certainly can't think of any from personal experience, as I didn't engage in much PvP or endgame PvE myself back in 2006.
One thing that surprised me is that apparently there is a considerably-sized community that loves and misses Vanilla's 20- and 40-man raiding. Kronos has a built-in boss kill tracker... just look at all those bosses being killed in real time, and that number is only going to go up once all the Nost refugees level up! It's funny because more recently large group raiding like this has earned a bad reputation, and a lot of Wildstar's troubles to retain players for example were blamed on its attempts to revive 40-man raiding. After seeing how things go down on Kronos, I'm confident in saying that the inclusion of 40-man raids by itself can't have been the game's issue. Hell, I'm willing to bet there are more people doing 40-man raids on private Vanilla WoW servers than in Wildstar even now. Why? Well, this video from Preach Gaming gives five reasons why the format was and is beloved by many:
(In fairness, he also has a video called "Top 5 Reasons 40 Man Raiding Sucked", showing the other side of the coin.)
Finally, there is PvP, which surprised me even more, because while I've seen a fair amount of negative comments about 40-man raiding, I've met even fewer people who had anything good to say about Vanilla's PvP. Classes weren't balanced, gear wasn't balanced, the grind for PvP ranks was only good for no-lifers. And who really misses Warsong Gulch matches that lasted forever?
Well, apparently there are a fair amount of people who do miss Vanilla PvP. While there are purists who say that world PvP died the moment battlegrounds were introduced, most will agree that it was generally still a thing at least on a smaller scale until flying was introduced. I reckon that few would admit it, but I think a lot of people also liked the imbalances, which is why so many Vanilla servers are flooded with warriors, mages and rogues. If your goal is to pwn noobs, being able to get an advantage right from the point of character creation is appealing. Put in a slightly less inflammatory manner to PvPers: they liked that not everyone was equal, that making the right choices and putting in extra work was very rewarding in terms of the advantages it gave you. To quote player Aieris from a thread on the Kronos forums on the subject:
You are realy [sic] rewarded for your grind effort. I (as rogue) was useless in PvP without any preparation. Blind/Vanish 5min CD and then what? Kited like hell. Then i farmed Thistle Tea, Free Action Potions, Engineering, trinkets and it got far more better.
Other reasons I've seen cited by people loving Vanilla's PvP are: gear being the same in PvE and PvP (meaning that it was easier to move between the two game modes and made the individual gear pieces more valuable), long AV matches feeling epic (personally I haven't experienced anything like that even on Kronos; I think it required people to be less knowledgeable about what they were doing than they are now, therefore causing the game to stall), and the classes' limitations making combat more straightforward (e.g. not everyone having an interrupt, heals or whatever).
Overall, this has really driven home the point for me that Vanilla WoW managed to offer an experience that appealed to different groups of people for very different reasons, even if there are certain common threads running through the whole thing (such as the need for greater investment being rewarded and getting to know people more naturally during gameplay). Everyone had their parts that they didn't like or at least didn't care about, but what they did like they loved so much that tolerating the downsides was worth it. It's noteworthy that this goes counter to the attitude that gets promoted more recently, that MMOs should just focus on their particular niche and cater solely to that audience.
Yes, things were different ten years ago. But it's remarkable how much of it still works.