Expansion is too grindy for casuals (has been improved a little bit though).
Essence system makes it terrible for alts.
“Required” content like IEs were far too mundane for hardcore players.
Lack of tier sets was bad for xmog.
Gearing progression is screwed up. You get a lot of pieces all at once and then it can take forever to get an upgrade. BIS is essentially dead.
Seriously, BFA’s target audience may very well be people who like to make spreadsheets or run endless sims on raid bots.