The zones they ruined in vanilla content basically made me level in dungeons and BG’s.
I hated Darkshore, Ashenvale, the Barrens, STV and Badlands. Not so much because I leveled through them multiple times but I had so many world PVP moments in all of them that it’s like they tore down my old playground. I hated losing South Shore as well for the same reason.
I only leveled through Thousand Needles once but did the warlock minion quest through there 2-3 times. It was incredibly iconic to be leveling on plateaus with rope bridges, really unique to any game. Then, they ruined it as well as Tanaris. Also along those lines, the pyramid quest to get to the top of the troll village in Hinterlands? One of my favorite group leveling experiences ever... ruined.
Oh and final gripe along those lines... the destruction of the world removed Benediction/Anathema.
I truly wish they’d layer these back to their original state. God knows with the work they did rebuilding classic they could use the same resources to fix the world.