We've already been through this kinda thing in game and its hard to deal with. Elemental used to be resistant to all forms of damage so it was exploited. People could cast an earth elemental and send it against all the earth elemental in a mine and then farm the ore without any worry. It then also forces mixing of class's and people like to not be limited. For example, Im full blunt on my bar right now, if I ran into a ghost I could not kill it. Sure, I can throw one of my earth spells on the bar. The dev's have balanced this well. Ghosts are very resistant to my bludge build but I eventually can kill them (and I have to have 900+ point in bludge skills to even do that). With my Earth build, I can take on earth elemental but it takes a long time. I think they have balanced this perfectly. It makes sense right? An earth elemental can resist strait up earth spell damage but my actually take physical damage from the actual impact of the stone.