Elemental (air) bloodline sorcerers get to treat their charisma as if it were 2 points higher for "all sorcerer class abilities."
What, exactly, does this apply to? Obviously any 3+cha mod abilities are affected, however, does this bonus apply to bonus spells for high charisma and saves?
I'm prone to say yes to both, but I'm more liberal on intrepretations. How it reads sounds like a yes to bonus spells per day, since spells per day would count as class abilities, but not nescessarily to saves.
What is correct?
Spell casting is a class ability.
This is demonstrable by the prestige class entries, the class features of the classes that have spell casting and monster entries of creature with the ability to cast "as a caster of type (x)."
As such it should apply to spell casting as well.
it is pretty sweet, especially if you are an ifrit, what with their racial bonus to charisma and fire bloodline affinity
I would certainly treat it that way, yes... especially since it says:
Elemental Affinity (Ex) Ifrit sorcerers with the elemental (fire)
bloodline treat their Charisma score as 2 points higher for all
sorcerer spells and class abilities. Ifrit spellcasters with the Fire
domain use their domain powers and spells at +1 caster level.
As a related question: Would a Sylph who is an Air Specialist Wizard gain +1 to their casting level for Air specialty spells? The rules state "Domain" which is for priest, not wizard. It seems odd that sorcerers and clerics would benefit but not wizards, but the wording of the rules seems to suggest air wizards would be screwed out of any bonus.