Glad I never picked it back up. Played Vanilla with close friends when it came out, stopped playing then picked up BC. Stopped playing, picked up Wrath.
Each time I started playing again, fewer and fewer of my friends were playing, and the game became less and less about the interesting story and more and more about grinding.
As someone who's played more or less continuously, I'm slightly mystified by this assessment. Every expansion they've told a tighter story, and more of it. Hellfire Peninsula and to a lesser extent the rest of Outland is the grindiest stuff left
In classic (which I leveled through plenty even if I never played it as endgame), most of the world was pretty disconnected. It had a lot of depth and charm that's been lost, but not so much 'story'.
In TBC, you sometimes got good arcs with significant storytelling, but this only happened in a few places (Blood Elf and Dranei starting zones, a little bit in Nagrand for Horde, some in Blade's Edge and Netherstorm, a little in Shadowmoon for attunement quests)
In Wrath, the entire expansion actually told a story, and each zone tended to have a good story or two on its own.
In Cata, they made everything cinematic: each zone told a story. More true of the new zones, but the rebuilt leveling zones had this too.
In Mists, they made the idea of a zone being comprised not of x quests but of storylines explicit and the progression of the expansion was the rise and fall of Garrosh Hellscream
In Draenor, they kept the mists-era storyline system and added even heavier phasing to certain zones to tell a sweeping story with media-like pacing
It's not necessarily better. The world feels smaller, like there's less to do and less to discover, but it's not grindy. Heck, that might be part of the problem. I was more engaged when there were difficult grinds like Netherwing than in the endgame of Draenor.