Originally Posted by Quellian-dyrae
I think you may need to revise your numbers quite a bit.
The mana pool seems very high compared to spell costs. If you can swing 18 Wis (trivial at higher levels for a secondary attribute), you are basically able to cast one 9th level spell per level with average mana as a mage (and that using the weaker 1d10+Wis/level). However, the regeneration rate is very slow, so it's not really a daily pool. This makes it even harder to properly gauge a caster's available power for a given encounter, allowing them to potentially nova to massive effect, but doing so could leave them quite low for several days.
Also, unless you're revising the spells to be on a 20 spell level system, by these rules people are casting higher level spells far faster (getting 9th level spells when the game assumes they have access to 5th level spells). This is only exasperated by Blindcasting, which basically lets you cast any spell you want at the same level that a caster would normally get access to spells of that level. Even setting this to half caster level, which more accurately represents current spell level access, you run into the possibility of artificial increases to caster level giving casters access to higher level spells early.
Lifecasting is also problematic. Converting hit points to spells is generally a good deal, because converting spells to hit points is already quite easy. A Lesser Vigor spell costs 1d6 hit points to cast, and restores 10 + caster level hit points over its course, making unlimited magic trivial at level 1. Likewise, even a single point of Fast Healing basically gives any caster basically limitless magic. There might be a bit of risk to it in combat, but you still have a plentiful mana pool to fall back on, and this is using fairly slow methods of healing. Snag a Heal spell, and you're basically always a standard action away from all the casting power you need. Basically, any hp-to-mp system needs some way to make sure the hit points can't be restored with normal healing.
Which...basically means casters under this system could fairly easily cast any spell they want an unlimited number of times per day.
This was exactly the sort of fine-tuning advice I wanted. First, I think I'll cut Lifecasting out entirely, since you have a point about it being too complicated. About the issues of the mana pool, I can alter that in a number of ways if necessary, but what you were saying about the mana pool being very high compared to spell costs was something of the flavor I was looking for, and I do like the idea that using up all your juice leaves you weak for a few days. On second thought, though, I might alter the rejuviantion effect to match that of Hp regain, which would make the recharge rate roughly proportionate to the mage's total power (good). I do admit that this runs a bit into Linear Warriors, Quadratic Wizards, but all D&D rather does that.
Again, thanks for the advice!