I feel the height differences affecting ranged attacks needs some major reworking. I get it that height can affect range of missiles (arrows, bolts, darts, thrown objects, etc.. ) and potentially affect damage on a very minor ammount (because of gravity slowing or speeding up said projectile), but that should not affect accuracy of missiles. Anyone that has shot a real bow, or slingshot with any degree of skill would know this. Yes you have to make trajectory adjustments, just as you would for ANY shot, but if you are "proficient" in the weapon you are using you would know how to adjust for that. I just don't understand the reasoning behind such extreme positive and negative adjustments for accuracy (chance to hit) in this game caused by elevation differences.
And Spells seriously should not be affected by height differences at all if they are LOS (line of sight spells). If you see them, you should be able to hit them without penalty. Magic resistance yes, but not elevation adjustments.