I would have liked to have seen the Beast Shape line of spells added to the spell list, possibly along with the plant, elemental, giant, dragon lines as well.
The familiar does seem a bit too weak to survive in battles later on. If you know you are going into a fight you can always send your familiar away to be safe, but if you get ambushed it will probably be caught in the crossfire. Were I DM'ing, I would change the familiar. I would add DR/alignment which matches the alignment of the witch, and if you are neutral you pick either good or evil. This protects it a bit from melee hits and may give it a chance to get away. It already gets improved evasion, so that helps vs spells. I didn't see any of the energy protection spells on the list for it, so no help there. I thought about using the druid's companion advancement table but I think that makes it almost too hardy for a non-combat focused creature.
There's nothing saying you can't purchase or craft specialty magic items for your familiar to help protect it, other than the limit of body space.
I also would have liked to see a hex that allows for polymorphing. Sure, baleful polymorph is on the spell list, but a minor hex would have been pretty neat.