Yes, when I attacked trolls, I did not care if I used fireball or lightning. Yawn, who cares. But, for one example, trolls should be vulnerable to fire, and perhaps evern regenerate physical damame. Now THAT would add variety and strategy to a battle. As for now, who cares . . . .
Exactly: Magic currently is boring, mainly because of lack of variety. A big step towards adding variety is adding spell resistance instead of defense. A further step would be to bring in resistances to specific elements.
I WANT to have Fire Elementals, that take double damage from water, get healed from fire, and hurt you when you attack with physical.
I WANT those trolls that need to be killed by fire or acid.
I WANT undead and vampires that take double damage from holy, and are immune to physical
What I do NOT want is 100 mobs that differ only in graphics and ATT/DEF.