A few weeks ago I played Pokemon Blue, one of my childhoods favorite games.
And while I did recognize the things that made me love it, there was so many broken or inconvenient things that made me shut it off. It's not the same, and I am not the same anymore.
Same with WoW. Going back to classic today would be fun, for the wrong reasons. "Really? Survival's final talent is a melee dot that deals less damage than REND?!", no LFR, no LFD, no glyphs, no dual spec, no stat conversion (spirit to hit), no reforge, no transmog, no arenas.. pvp talent trees, pve trees, leveling trees, only warrior tanks, hybrid? go heal or you're useless.
Difference with WoW today and back then, the devs now know what they are doing. oh plate with spirit and agility, how I miss you.