TBN isn't 'problematic' in terms of the MP requirement. I know that there are players who want it to be completely foolproof to use, but I would much rather those players learn the damage patterns of the fight. It's not difficult to work around. It'll probably just end up becoming a flat 25% shield on a 25s recast with no MP cost attached, knowing how people are going on about this. Good for them I suppose.

It's actually quite difficult to come up with a way to improve on TBN. I don't think that Oblation as an 'extra' mitigation move was ever necessary, but since they've gone through the effort to make an animation for it, sustain is the only direction I could see this getting better in a meaningful way. You could apply the healing as a HoT after the fact, but that's pretty similar in style to HS.

I do feel like Dark Arts in its present implementation is a wasted UI gauge and I'd like them to do something more with the mechanic. But that's a different issue.