So, in a campaign of mine I play a witch and, since it fits the character concept, plan to dip Loremaster for the sweet boni to knowledge.

One of the prerequisites is Skill focus (knowledge x) and since that feat is otherwise rather lackluster, I'm searching for something to use it for: this was when I stumbled upon Eldritch Heritage.

The highlight to take would obviously be the arcane bloodline to get a familiar, but witches already have one. Can't have another or a bonded item, can't you?
Nearly everything else seems to be weak blasting- to weak to take as a feat around level 13. Am I missing something? Is any bloodline ability worth taking through Eldritch Heritage?