Enmity overhaul pretty much. Enmity combos would have to have their generation increased by x5 or even x10. I am sure you have seen the chaos when tanks fight for aggro because they are both in tank stance.

This removing of tank stance is literally putting all tanks in a permanent tank stance. Forcing a playstyle on all tank players.

One big problem is every expansion there are general enmity problems all around. Look at the patch shortly after 4.0 released when they had to make several enmity changes. All the buffs to diversion.

Removing tank stance and you have to rework all 3 job gauges, enmity, enmity combos and role actions, alongside the existing job changes and the tp/mp change.

I have faith in the dev team but you have to remember the effort to fix healers as well. I just dont think they can do all these changes without something going horribly wrong.