Thaumaturge

The thaumaturge is a wielder of arcane magic that accesses the power to cast spells from magic energies he calls mana. While these energies allow him to modify the spells he cast in wondrous ways, and can be used to power even the highest spells at an early time in their magical career, he only has limited access to these energies.
Alignment: Any
Hit Die: d6
Starting Wealth: 2d6 x 10 gp (average 70 gp.) In addition, each character begins play with an outfit worth 10 gp or less.
== Class Skills ==
The thaumaturge’s class skills are Appraise (Int), Craft (Int), Fly (Dex), Knowledge (all) (Int), Linguistics (Int), Profession (Wis), and Spellcraft (Int).
Skill Ranks per Level: 2 + Int modifier.
== Weapon and Armor Proficiency ==
Thaumaturges are proficient with the club, dagger, heavy crossbow, light crossbow, and quarterstaff, but not with any type of armor or shield. Armor interferes with a wizard’s movements, which can cause his spells with somatic components to fail.
== Mana ==
The thaumaturge fuels his spells via an arcane energy pool of mana. At the start of each day, a thaumaturge gains a number of mana points equal to his level + his Wisdom modifier.
== Spells ==
A thaumaturge casts arcane spells drawn primarily from the sorcerer/wizard spell list. He can cast any spell without preparing it ahead of time. To cast a spell, a thaumaturge must have a Wisdom score equal to at least 10 + the spell level. The Difficulty Class for a saving throw against a thaumaturge’s spell is 10 + the spell level + the thaumaturge’s Wisdom modifier.
The thaumaturge does not have spell slots or spells known. Instead he may cast any spell on his class' list by spending points from his mana pool. To cast a spell the thaumaturge spends a number of points of mana equal to the spell's level.
== Metamagic Alteration ==
The thaumaturge may not select metamagic feats. Instead he may modify his spells with any metamagic feat by spending a number of points of mana equal to the number of spell slot levels higher the metamagic feat increases the spell.
For example a thaumaturge would normally spend 1 point of mana to cast magic missile. He can apply the 'fearsome spell' metamagic feat (even though he doesn't have it) to magic missile making it cost an additional 2 points of mana for a total of 3.
== Power Level Alteration ==
The thaumaturge may modify the power with which he casts spells.
=== Undercast ===
He can cast a spell at any caster level lower than his actual caster level. For example if he was caster level five but wanted to cast magic missile as if he was caster level three, the spell would only shoot two missiles instead of three. Doing so does not modify the mana cost.
=== Overcast ===
He can cast a spell at any caster level higher than his actual caster level. For example if he was caster level three but wanted to cast magic missile as if he was caster level five, the spell would shoot three missiles instead of two. Doing so modifies the mana cost equal to the number of caster levels above your actual caster level you are casting the spell (so in this example the mana cost of the magic missile goes from 1 to 3).
== Behind the Scenes ==
The goal was to make a mana-based casting class. The idea was to allow the player to make the choice between casting a lot of spells, or a few powerful spells.
I chose wisdom as the main ability score for the class because wizards use intelligence, and sorcerers use charisma, so I figured having something different would be good.
The class can cast high level spells before any other primary spell-casting-class is able to and has all spells on it's list available to it from the start. This is balanced with it being able to cast the lowest number of spells compared to every other primary spell-casting-class. Even with the benefit of being able to cast high level spells from level 1, many of these spells aren't going to grow powerful until cast at a higher level anyway and will use up most or all of their spell-casting capabilities for the rest of the day (for example 'ball lighting' only creates two globes of lighting whether your casting it from caster level 1 or level 10. It isn't until level 11 that it gets better because it states "for every 4 caster levels above 7th, you create an additional globe." Even with the overcast ability it would cost a lot of mana to use this spell's higher level benefits before the game can handle it.).
Being able to modify spells with metamagic feats without needing the feats is offset by using the already limited resource with which he casts his spells.
Even if someone tried to powergame this class the player would be handicapping himself in some ways to make the trade. For example if he had 9 points of mana in his pool at level 1 by throwing everything he had into wisdom, then he can cast wish at level one, but his pool is used up for the rest of the day so he can no longer cast spells.
Leveling up is boring in some ways because the only interesting thing the class is gaining is mana. Do consider however that when you look at the sorcerer class the only interesting thing they are getting is new spells & spells per day, as well as bloodline stuff which is mostly spells anyway.