DogBackward said:
At the most basic level, you have a mana pool that regenerates at the rate of one per round, as long as you don't cast a spell in that round. Simple spells cost a certain amount of mana, and consist of the simple, easy-to-use effects that aren't a big deal if they can be done all day (albeit with a rest period of a few round sin between to let your mana regenerate), such as simple damage, defense, and such things.
Then you have Complex spells, which do the more powerful or bigger effect. These include Cure X spells, summoning spells, Polymorph, and the other big ones, as well as any spell with a casting time of longer than one round (because it makes sense... they take longer to cast because they're... complex spels). The thing is, that any Mana spent on a Complex spell isn't regained until you get your 8 hours of rest.
It comes together with both ideas. You can do the basic stuff all you want, with a few rounds of rest in between. But you still have to manage your resources when using the bigger, more widely effective spells. Not only because you won't be able to use the Complex spells but so many times a day, but also because using Complex spells means you have less Mana left to use your Simple spells, as well. Best of both worlds, as it were.
You could also adapt this format to work with spell slots.
Have you read The Book of Nine Swords? I'll phrase my thoughts, sort of, in terms of BoNS.
(And I just have to throw this thought in since my brain is racing-- possibly the most important resource available to PCs, particularly in high level play, is the
action. There is a lot you can do to balance combat encounters just with managing the resource of actions. The recent article about "The Big Six" magic items touches on this tangentially.)
To continue:
Simple spells are either always ready, or can be refreshed in a simple way, possibly not even requiring a significant action to do so.
Complex spells either cannot be refreshed until the end of the encounter, or must be refreshed using a significant action.
Exotic spells (to continue your format) cannot be refreshed more than once per day. If you ready an Exotic spell into one of your spell slots, you get to use it once per day.
Generally speaking, as a designer, I am afraid of spell point systems, because of the tendency to "go nova" as Merric pointed out. They just never really work very well in tabletop play, IMO/IME.
On the other hand, they are very familiar to today's generation of computer RPG gamers. That's a big plus.
EDIT: Can someone give me an example of a reserve feat or tell me which WOTC product introduced them?
EDIT2: You could remove healing spells from the "spell list" entirely and only allow them to be cast by spontaneous conversion. Any readied spell (ie, spell slot) can be converted to a healing spell at any time, removing the prior spell from readied status until the next time the spellcaster can ready spells.