The UI needs improvement.

I want to be able to turn off all status icons on party members except for debuffs. In the heat of combat it's too hard to tell when someone has a debuff I need to remove when everyone in the party has a lot of icons. I don't have time to let the tank die while I'm looking through 20+ icons to find the one that's a debuff.

The mobs' icons aren't much better. I have to guess at when my DoTs are going to wear off. When the mob has half a dozen of each of my 4 DoTs the fact that mine are slightly tinted a shade of green that barely looks different than white doesn't help. I want to be able to turn off all DoTs on mobs except mine.

Not sure about that, since I still want to see if my party has Regen/Stoneskin up. A better soultion would be to make them easier to see, such as prioritising debuffs as being on the far left of the list or making them flash.

An option to turn off other players' debuff icons on the mobs I would be grtateful for.

Debuffs are already sorted to the left.
The problem is you can't see timers on them.