Well, i thought about that, but i prefered to give the prestige an animal companion progression and improved skill list (along with more skill points per level). Also it gives you a thousand faces. So, it only loses venom immunity and two caster levels from a straight druid.
Ah, I missed that. You might then want to separate them into two different class abilities, as you can qualify for the prestige class without an animal companion.
I'd do first level as 'Wild Shape, Animal Companion'
'Wild Shape: Your Eldritch Disciple Adaptation level stacks with your other class levels for the purpose of determining your ability to Wild Shape.
Animal Companion: You gain an animal companion as a Druid equal to your Eldritch Disciple Adaptation level. If you already have an animal companion from another class, the levels stack to determine your effective Druid level for your animal companion.