This is an attempt to generate interesting Arcane casting base classes that do not have access to high level spells, but are still worthwhile.

The idea is that being a Wizard requires both natural aptitude and study. Characters who have the aptitude can choose not to develop it, or choose to work at it.

A Magical Adept/Other class is someone who is not attempting to develop their natural talent.

A Magical Adept/Wizard class is someone who has chosen to study the art of magic and master it.

Both of these classes have d4 HD, and use the Sorcerer / Wizard skill list. They both get 2 skill points per level, and have access to the Wizard weapon proficiencies, and have Good will, and poor Reflex/Fort.

Magical Adept

Special: your Adept level can be no higher than 1/2 of your character level, rounded up. This includes bonus level effects from PrCs.

Casting is Charisma-based, but there is no min stat requirement to cast a spell of a particular level. Charisma gives additional spells per day, and a bonus to spell DCs.

Spells per day/known:
Code:
    0   1   2   3   4   5   6
1  5/3 3/2  -   -   -   -   -
2  6/3 4/2 2/1  -   -   -   -
3  6/3 5/3 3/2  -   -   -   -
4  6/3 6/3 4/2 2/1  -   -   -
5  6/3 6/3 5/3 3/2  -   -   -
6  6/3 6/3 6/3 4/2 2/1  -   -
7  6/3 6/3 6/3 5/3 3/2  -   -
8  6/3 6/3 6/3 5/3 4/2 2/1  -
9  6/3 6/3 6/3 6/3 5/3 3/2  -
10 6/3 6/3 6/3 6/3 6/3 4/2 2/1
Other:
Code:
   BaB  Specials
1  +0   Intuitive Casting
2  +1   Overpower(1)
3  +1   Metamagic Feat
4  +2   Overpower(2)
5  +2   Metamagic Feat
6  +3   Overpower(3)
7  +3   Metamagic Feat
8  +4   Overpower(4)
9  +4   Metamagic Feat
10 +5   Overpower(5)
Intuitive Casting:
May apply metamagic spontaneously. If a spell fails ASF, the Adept may make a concentration check against DC (15+spell level*2) and attempt to cast the spell again as a free action.

Magical Adepts pick a school of magic that they are attuned with. Spells from other schools of magic require a spell slot 1 level higher.

At 4th level and every even level afterwards, the Adept adds a +1 DC bonus to all Arcane spells cast by the Adept.

The Caster Level of the Magical Adept is equal to twice their class level, or their HD, whichever is less.

Overpower:
A Magical Adept may overpower a spell. This requires an additional full-round action to cast a spell. A spell of up to 1/2 of the Adept's level is consumed, and that many metamagic points are availiable to boost an existing spell.

Damage done between the first and second round of casting requires a concentration check, or the spell fails.

Wizard:
Special: Your Wizard spell casting level may not exceed one's level in some other Arcane Caster class. This includes bonus level effects from PrCs.

Wizards casting stat is Intelligence. They require an intelligenct of 10+spell level to learn a spell of that level, they gain a bonus to spell DCs equal to their intelligence bonus, and additional spells per day.

Spells/day:
Code:
   0   1   2   3   4   5   6
1  3   2   -   -   -   -   -
2  3   2   1   -   -   -   -
3  3   3   2   -   -   -   -
4  3   3   2   1   -   -   -
5  3   3   3   2   -   -   -
6  3   3   3   2   1   -   -
7  3   3   3   3   2   -   -
8  3   3   3   3   2   1   -
9  3   3   3   3   3   2   -
10 3   3   3   3   3   2   1
These spells must be selected according to the rules of another arcane casting cclass the Wizard possesses.

Wizard Specials:
Code:
    BaB   Specials
1   +0    Learned Casting, Scribe Scroll
2   +1    Summon Familiar, +1 DC to all spells
3   +1    Bonus Feat
4   +2    +1 DC to all spells
5   +2    Bonus Feat
6   +3    +1 DC to all spells
7   +3    Bonus Feat
8   +4    +1 DC to all spells
9   +4    Bonus Feat
10  +5    +1 DC to all spells
Learned Casting:
A Wizard may learn up to their intelligence bonus in spells per level spell level. A Wizard who suffers ASF when casting Wizard spells loses their action.

The Caster Level of a Wizard spell is equal to twice their Wizard class level.

At level 2 and every even level after, the DC of the Arcane Spells cast by a Wizard optionally increases by 1. If this feature is used, then the spell cast will suffer ASF, and if the ASF fails the action is lost.

Bonus Feat:
A Bonus MetaMagic or Item Creation feat.

Summon Familar: (this doesn't suck)
A Wizard's Familiar is an extension of the Wizard's essence. It appears as a tiny animal or homoculous.

If it is forced to move more than 30' away from the Wizard, or is killed, it dissipates and cannot be recalled for 24 hours.

The Standard Familiar has the following stats:
HP equal to the Wizard
HD equal to twice the Wizard's class level.
Saves equal to the Wizard
SR of three times the Wizard's level
Mental stats equal to the Wizard.
Constitution equal to the Wizard.
1/2, rounded up, the Strength of the Wizard.
Dexterity 4 greater than the Wizard.
A Luck bonus to AC equal to the Wizard's class level.
BaB equal to the Wizard.
Melee damage equal to 1d2 lethal or non-lethal.
The Weapon Finess feat at level 1, and 1 additional feat every 3 HD.
Tumble/Hide/Sneak/Spot/Listen skills equal to the Wizard's class level, or the Wizard's skill level, whichever is better.
Move of 20' ground.

Optionally the Familiar may fly 20' [Good]. If so, it has half as many HP as the Standard Familiar.

The Wizard may recall or dismiss his familiar as a standard action. By default, the Familiar is assumed to be resting or hiding on the Wizard's person.

As a swift action, a Wizard may cast a touch spell through his Familiar of a level up to 1/2 of the Wizard's class level, rounded down. The Familiar must, naturally, make the touch attack to deliver it.

If the Familiar is in contact with the Wizard, any spells that effect the Wizard may at the Wizards option either effect the Familiar or not. This includes detrimental area spells, such as fireball. This includes personal range spells.

The Familiar is a part of the Wizard. The Wizard sees everything his Familiar sees. The Familiar acts on the Wizard's turn, and makes a Standard Action/Move action just like the Wizard.

...

Any opinions?

This probably works better in a campaign that starts at level 2.