Remember in Diablo how monster tooltips gradually showed more information as you killed more of them? The first time you met a zombie it would say "zombie" and (say) the 50th time it would also say like "Resists cold" or something else. It would be neat in this game if the first time you met a mob it just said "Scarlet Defender" but the 50th time it might give you information like "heals others" or "flees when wounded."
I don't think it would be hard to make an addon that gathered spell names and put them in the tooltip. I can see it using a whole lot of memory. Or are there ways around that now?