I want some UI improvements:
1. Larger current target marker.
When changing targets with "Tab" it's hard to see, which one is selected. I suggest option to have huge (really huge) arrow above target and also thick outline around it. Obviously it should be possible to turn it on/off.
2. Casting bar
I want it to be much better visible than now. May be change color to something brighter and add outline to it. Again, it is possible to have it style configurable (may be even several different styles).
3. Reduce visual clutter
FFXIV has very useful setting to limit displayed animations. It has 3 groups: self, group, other players. For each group it has 3 positions: full, limited, none. I want to have similar settings in this game, because even my own animations sometimes feels too flashy. And several players' attacks are absolutely unreadable.
Also I suggested same settings for PvE enemies, especially bosses. To many flashes, explosions and other effects.