Currently the list available are:

summon charm magic weapon bash pierce slash fire cold light lightning acid poison negative holy energy mental disease drowning sound wood silver iron kill

First, I would say change wood to earth, as I honestly can't picture any sort of character, pc or npc going: OW! I got a splinter and it hurts like Gazar!@

Second would change summon to transport, which would deal with not just summons, but gates and nexus, as well. Even with auto summon off, it shouldn't be gauranteed success.

To illustrate the example of which I think would make these better, let's pick on Minotaurs, with the above list. The scale will go from -25 to 25 for simplicity. -25 meaning 25% more damage/success, 25 meaning 25% less damage/success.

transport - 0

charm - 0

magic - -4

weapon - No PC should gain this

bash - 6

pierce - -3

slash - 3

fire - -17

cold - 13

light - 0

lightning - 0

acid - -4

poison - 3

negative - 0

holy - 0

energy - 0

mental - 0

disease - 7

water - 0

sound - 0

earth - 0

silver - 0

iron - 0

kill - Only to Lich

+4 overall. Depending on the race and their other abilities, I think a +/-5 overall would be acceptable. These are just arbitrary numbers to show a point. Equipment can hold these as well, increasing or decreasing ones resistance/vuln to it. I think that it should be limited to Imp level for better scrutiny of how much and where it is being placed in the game. There should be no reason that a piece should have more than 5, and not increased by enchant armor.

I think that this system allows for a higher level of balance amongst races, and give slight bonuses/weaknesses to areas that have previously been neglected.