Magic Mechanics

[chuckro]

So, I was musing on magic system mechanics for various roleplaying systems, and I figured I'd put this out there: Of the following, which do you prefer as a GM or as a player? Why?

1) Spells per day, typically that need to be memorized ahead and are expended when cast.

2) Spell-slot or spell-points systems, where each spell uses up a certain amount of MP or a slot that you regain when you rest. (A variation on this is spell-fatigue, where you don't get a MP limit, but casting tires your character and give you penalties to other rolls.)

3) Backlash systems (Paradox, primarily), where you have theoretically limitless magic, but risk backlash from using it/using it too much/using it in certain ways.

4) Percent-failure systems, where you again have theoretically limitless magic, but have to roll to succeed in using it and/or have a fixed percent-failure chance.

The follow-up/related question is whether you prefer free-form magic or a set spell list. And I'm not going to p[ost my opinions until I get a few responses, so as not to bias my sample.

Comments

[chuckro.livejournal.com]

Good points, bad example: Polymorph Self will turn you into any number of splatbook-described hideously-overpowered forms. War troll? Chain devil? The wizard will be a blender for the purpose of this combat...

[jethrien.livejournal.com]

Ok, true. Sorry, I'm actually having trouble remembering some of the less generic spells right now, given that I never used them. You know what I mean, though - you find yourself needing "kill stuff" spells, and you've got some carefully calibrated spell that would be exceedingly useful in a handful of situations, but will not actually keep monsters from eating your head.

[edgehopper.livejournal.com]

See my cleric's memorization of Banishment or Zone of Truth for a better example. Or the frequent taking of spells that work on all living creatures, only to get into a fight with undead.

[jethrien.livejournal.com]

Exactly. And the DM can't really tell you, because that would ruin the plot, but you have to pick spells with no hint of what would be useful.

And this is why I probably will never play anything but spontaneous casters again for D&D magic users.