So Sorcery is supposed to all be about your bloodline, right?
Then here's an idea to consider:
First of all, make the sorcerous bloodline abilities into class feats with appropriate prereqs and give the sorcerer a class feat at each relevant level, so that they aren't actually the most locked in class.
Second, allow all Sorcerers to take any Bloodline class feat as an Ancestry feat! It would allow for a sorcerer to focus on his otherworldly heritage at the expense of his "demihumanity".
