Spell casting with a mana style system

[Verumsui]

Hello! I'm going to cut right to it and ask for help on redesigning the spell casting system to work more on a mana basis than a spells per day one.

This is what I have so far;

The "mana" is Spell points.
Spell points = The total number of spells there are among all the spells per day you can cast.
Example; A 3rd level Sorcerer, which normally has 6 0-level and 5 1st-level spells would have 11 points, plus those gained from bonus spells. (6+5+x[X= bonus spells])
A 5th level Wizard, 4 0-level, 3 1st-level, 2 2nd-level, 1 3rd-level would have 10 points, plus those gained from bonus spells. (4+3+2+1+x[x=bonus spells])

The spell point cost for the spells would be as follows;
0-Free? (Still undecided) 1st-2, 2nd-3, 3rd-5, 4th-8, 5th-12, 6th-17, 7th-23, 8th-30, 9th-38

This would mean that a 20th level sorcerer with 30 Charisma(Bonus spells for this charisma score are included on this list) would be able to cast;
38 1st-level, 25 2nd-level, 15 3rd-level, 9 4th-level, 6 5th-level, 4 6th-level, 3 7th-level, 2 8th-level, 2 9th-level. (this is or, not and, so if they were to cast 2 9th (76 points they could only afford a level 1 before they were out))
The maximum number of spell points a level 20 wizard could have before bonus spells are applied is 40, the maximum spell points for a sorcerer of the same level under the same condition is 60.

In combat spell casters would be able to regenerate spell points. This happens during any round in which the caster did not cast a spell higher than 0-level. The spell points returned are equal to Wisdom modifier +1/2 caster level.
Example; A 6th level sorcerer with a wisdom score of 16 would gain 3(the wisdom modifier) + 3 (1/2 caster level) = 6 spell points.
Example; a 16th level wizard with a wisdom of 18 would gain 4(wisdom modifier) + 8(1/2 caster level)=12 spell points.

Out of combat caster would be able to regenerate spell points as well, meaning they could be at least partially refreshed before the next encounter starts. The rate at which spell points regenerate out side of combat is wisdom modifier * 1/2 caster level per hour.
Example; The same 6th level sorcerer would regenerate 3 (wisdom modifier) * 3 (1/2 caster level) =9 spell points per hour
Example; The same 16th level wizard would regenerate 4(wisdom modifier) * 8 (1/2 caster level) = 32 spell points.

This is a rough system, and I would appreciate any help people might have. Are there any ideas or suggestions you can think of? is there any obvious way you might be able to abuse this? Is there anything I should add or reconsider?

[ComaVision]

Why not just use/refluff Psionics?

[Buufreak]

I tried the spell point system once. It seemed like a great idea, like it would give that much more flexibility to the party. Instead, they burned through their resources so incredibly fast, they were always shooting themselves in the foot and had to leave about 3/4 of the encounters to the not so op'd archer. That could be an observation of lack of resource management, but it definitely is something to consider as a potential issue.

[danzibr]

Why not just use/refluff Psionics?
This was my initial thought.

I tried the spell point system once. It seemed like a great idea, like it would give that much more flexibility to the party. Instead, they burned through their resources so incredibly fast, they were always shooting themselves in the foot and had to leave about 3/4 of the encounters to the not so op'd archer. That could be an observation of lack of resource management, but it definitely is something to consider as a potential issue.
Yeah, this seems like a big problem. "Hey, with all those SP I can spam my biggest spells!"

As far as constructive criticism goes, don't just add the number of spells. Add number of spells*spell level, except maybe free cantrips, or .5 for those.

[Verumsui]

This was my initial thought.

Yeah, this seems like a big problem. "Hey, with all those SP I can spam my biggest spells!"

As far as constructive criticism goes, don't just add the number of spells. Add number of spells*spell level, except maybe free cantrips, or .5 for those.

Due to the cost of the 9th/8th level spells, only sorcerers (who have higher spells per day normally) of higher level and with a good charisma score can cast multiple without waiting several turns in-between, yet the moderate level spells they could cast multiple of with relative ease.

[Keltest]

I use a mana system, and it usually works out pretty well.

Something you may want to be wary of is how many active spell slots you give wizards, since if they can cast a spell multiple times while only having it memorized once, they will quickly outstrip sorcerers in terms of usefulness even if sorcerers have more mana overall just from the sheer variety of spells they can pump out.