if one plays a non-draconic sorcerer bloodline, but then takes eldritch heritage (draconic), would one then meet the prerequisites for the dragon disciple prestige class?
eldritch heritage gives you a bloodline... the class reqs say that if you're a sorcerer, you have to have the draconic bloodline, which you do...
then, if that is allowed, my next question is about the class' blood of dragons ability...
this allows you to add your prestige class levels onto your draconic sorcerer/bloodline levels... but eldritch heritage bases the sorcerer/bloodline level on your character level, which includes your prestige levels...
so, a sorcerer 5/disciple 5 would have an effective bloodline level of (10-2)+5=13, granting them ability upgrades beyond their level, like acid claws... or a more powerful breath weapon or AC, if they also take improved eldritch heritage...
as far as i can tell, this is all ok, by RAW.
conceptually, i don't like the thought that a 'weaker' bllodline would be able to capitalize on the class in a way a straight draconic sorcerer could not, but it looks like they could.
i am playing a draconic sorcerer/disciple currently, and was toying with the thought of eldritch heritage, when i saw how blood of dragons could be bent, with the right planning.
Eldritch heritage doesn't give you a bloodline so you can't use it to qualify. Your two choices are taking the draconic bloodline, or the crossblooded to have draconic and something else.