yeah ofcourse it is, but if everyone gets it baseline- its just horrid having a pack of mobs and every frame is red, same size, same color, no abreviated names support.
Its unpleasant for the eyes and to sort through. Thankfully in pvp this is not the case- its very easy to see which target is which. and that takes off some cognative load and makes the overal experience more pleasant. Or atleast there is a checkbox to enable class colors. I think something similar should exist for mobs and their classification- so either distinguish between luitenant and elite mobs in dungeons or even between casters and melee aswell.