For the first time I am actually going to say that I am ecstatic that Classic WoW Beta has been popular among a ton of new age mmo gamers and streamers. Let's define what a 3rd mmo player is. These definitions are just based off my person opinion but one can make an argument that it could be valid.
1st Generation MMO Player -- Is someone who started with Ultima Online, Everquest or anyone pre-WoW era.
2nd Generation MMO Player -- Is someone who started with Classic WoW
3rd Generation MMO Player -- is someone who started playing mmo's with Black Desert, Legion WoW Expansion etc.
Over the years you can clearly see that the core gameplay and design philosophy has changed. More modern designs are about getting players to completing specific generic objectives for low substance rewards. Most of the time it's a solo game that you happen to play with others. For higher end content grouping is more involved.
I recently watched a video by Bellular Gaming, he does pretty good videos and I agree with him on most of his design philosophies but in his latest, he brought up a point I have been trying to make for years.
Classic WoW is fun for these 3rd Generation MMO players because it actually has RPG elements integrated in the core gameplay. That is just the ingredients. What makes it all come together in a cohesive form is the "Work" that compliments the "relationship" to the "Work".
So what is this "work". It's essentially the leveling process, the exploring process in which is the essence of the core gameplay of an mmoRPG. The "relationship" is the community in which your Character/Player needs to help accomplish that "work".
Take a gander at retail WoW right now. The core gameplay is stale, lacks substance and it's merely a lobby game. Your character is powerful, the environment isn't dangerous and you're not as dependent on players anymore. What I mean by that is, the sense of Community is bland in retail WoW. The "relationship" to the "work" has diminished significantly.
Now, take a gander at Classic WoW (Which is a dumbed down version of EQ), but still. Classic WoW had more RPG elements and the "relationship" to "work" was stronger. Your character wasn't all powerful. You needed a few players to help venture the world. Quests didn't hand hold you as much so that dependency of community grew.
I have been a member on this forum for a while and have always advocated that there is a MARKET for the First/Second Generation MMORPG in the modern era. I still truly believe that and the surge of popularity among the Third Generation MMO player for WoW Classic, to me at least somewhat proves that. I have been saying for years. If we can have access to an mmorpg that is a harmonious blend of Everquest + Classic WoW in the RPG element factor, that might be the next 'big' thing.