Back to the conceptual thing, and 1 step ahead, the resistance based spells need some general differenciation, to offer a mix of strategy. I am specifically adressing the death realm, because it has the majority of res_based spells. Right now, the choices are almost irrelevant, the variety of effect does not suit the game and the situations you are likely to encounter.
Below, I use three criteria, mana economy, percentage of success, strength of effect.
Resistance spells can have
- economical value,
it has relatively poor % of success (0 or -1 to save), but it is VERY cheap (but it has good effect), so if you throw it a lot, you'll eventually get a result (with Asfex' model). Also, when you have last 5-10 mana, you cast this. Many of current spells work like this, but they are often wimpy, Weakness for instance (see below what I think of it). Black sleep, and it should be cheaper.
- "lottery" value
- you face a very strong opposition (yes, even the magic creatures!), but spell X can save your skin, if you're lucky. Of course, X has good % of success (which is still probably not enough against Sky drakes) but it is VERY expensive (60-80 mana), so you probably cannot throw it twice (and increase % of success). Think of good Cracks call, but resistance based (it can have -7 or -8 to save, for me). Possession, Creature binding were thought to be this, but they are wimpy. Word of death, if much stronger and more expensive.
"daily bread" value
- Simple spell with very small effect, but it WORKS, has high %. Medium cost (15-20 mana). Can be used everyday. These I miss the most. Weakness used to be automatic. OK, not this back, but I would very much like to see it back with a big -5 to save, bigger cost. Weakness should be the one, for me, the daily bread of death magic. Every realm has a common "daily bread" spell (web, confusion, heroism, fire bolt, fire elemental, phantom warriors...), bar Death magic. That is nr 1 reason why I dislike to play it. Also, I think that Confusion is too poweful to be "daily bread" type of spell.
normal, strong spells
should be some of those that are Rare and maybe the uncommon ones. They should be solid spells, good % (-2..-4 to save), expensive (35-55). Now Petrify, Disintegrate, Wrack, question mark is over Possession, Vertigo. Many of these fail to do the "strong effect" part. They are wimpy.
"let's hurt him at least" spells - You face a lost battle but you want to do harm to the opposition. You have a spell that can utterly destroy one of its unit, good %, higher cost. Now Word of death (stronger, please, and it should come earlier in the game, uncommon). Otherwise, it is only Cracks call, but there could be a resistance based spell able to quickly and fatally harm the opposition. (And no, Petrify is not the right one, because Nature already has THAT one.)
The main point is to give you the MIX of these, instead of 1 spell that works like a miracle and a bunch of economical value spells, that feel totally interchangeable. This will make this spell branch attractive to play, the concept will work.
Every spell should have a distinctive situation, distinctive combat moment for its use.