Originally Dps could pull aggro off a bad tank, not all moves gave enmity and if I remember correctly most of those moves only gave enmity while in tank stance. This added consequences to the game, DPS and healers had to use moves to lower their aggro.

Tanks stance wasn't perfect, and at high-end ARR the meta was to tank without it. However removing it was a terrible plan IMO. Instead they should have made aggro gain more difficult if you weren't stance switching, made tank stance OGCD and then in each expansion they could have focused each tank classes mechanics around their stance and subsequently TP which I'll get onto next.
This is a lie. Everyone who tanked in SB knows that agro management wasn't a thing for the MT, it was the OT to voke shirk on cooldown and everyone else managing their own hate with diversion or lucid. Get your head out of the clouds and remember the truth. It was not tank mechanic, it was the party mechanic that they hated to do.