I get it now and i agree with you...i like the -ve resisance thing...it could be like you picked up some sort of cursed armour..... <img src="/ubbthreads/images/graemlins/idea.gif" alt="" />

Some(not all) armour when identified could be cursed...i.e they decrease...ethier...strength..agility e.g or as you suggest resisances...but why stop at that...lets make it so that when you wear them....you cant take them off <img src="/ubbthreads/images/graemlins/devil.gif" alt="" />!!!!
If you are lazy and didnt bother to identify the armour...then you are still cursed <img src="/ubbthreads/images/graemlins/evilgrin1.gif" alt="" />

Instead you need to lift the curse..this could be a skill whereby there are 5 levels of curses.
History...the dead whom have fallen curse anyone who wears their stuff...curse strength depends on the level of curse.

LEVEL 1-10...Spirit...anyone with 1 skillpoint plus an item say 1 heaing potion
Level 11-20...Poltergiest ========2================================> 1 mana potion
Level 21-30...Banshee ==========3=================================> 2 healing potions
level 31-40.....fallen mage=======4=================================> 2 mana potions
Level 41-50.....neferal being=====5=================================> 2 health and mana potions

These weapons/armour relate to those which may be dropped by an enemy or those which can be randomly found.
You are only cursed when you wear the items not if you pick them up.
These items will go for cheap as merchants wouldnt want to by them but some evil or normal merchants might pay a good sum...so look around.

Tragic