The drawback for Confusion is slow attacking speed, harder for the Espeon to dodge enemy's attack, and attacking less hits because of constant need to dodge. However this is both player dependent and is prone to variation, and Confusion charges faster too. Some do as good with Confusion, but some do better with Zen Headbutt instead.
I am not sure with futuresight, but I will find somewhere to test futuresight and psychic to see how it goes.