And this is what I came up with: The reason I posted it here rather than in suggestions, is because I realise I will need help to crunch the numbers, as well as get an idea of what people think.
So without further ado... Here is what I've come up with so far!
Elemental savant (Wizard path)
Requirement: Wizard with general school (no specialisation)
*Chooses an element at creation of the character, either Fire, Ice(water), Acid(earth) or lightning(air)
*Gains resistances to their chosen element every 5 levels (5, 10, 15, 20) (In increments of five.)
*Every damaging spell the caster uses turns into the element they have chosen- Even magic missile. They cannot change elements of their spell.
*Every 3rd level, the elemental savant’s spells apply a “vulnerability” to their element upon casting it at foes with immunity, starting at 10 % increasing by 5 % every 3rd and stopping at 55 % vulnerability upon cast (Might need some tweaked numbers?)
*Every 10th level, the elemental savant’s spells apply vulnerability to those creatures without immunity to their elements, starting at 10 % And halting at 30 % (Once again, the numbers might need to be tweaked.)
*Gains the ability to turn into the element they have chosen at level 15 (If its not too much, that is.), And can turn into an elder elemental at level 25.
Cons:
*Loses their wizard bonus feats (If possible?)
*Loses access to the Necromancy school, as well as the ability to summon creatures with the conjuration school.
*Cant pick EDK, Nor EMA.