It would be fun to slowly add little vanilla friendly bits and bobs to wildercraft, and I think a saddle that allows you to control Endermen, spiders, skeletons would add fun without being too intrusive or unbalanced to vanilla gameplay. Probably would be hard to implement mob behavior changes that way. Just a little thing to think on.

i honestly think that that is a terrific idea! though how exactly do you think it would work? like a horse? or perhaps like a pig or strider where you need a certain item