Think him and Cook will make a good opening partnership, Cook might not be international standard in the short format but at this level I think he'll shine.
I would normally agree with that but one thing to look out for is whether T20 takes another jump forward this year.
They've been playing T10 in Sharjah and I think it's going to raise the bar for batting like T20 has done for 50 overs cricket. Mohammad Shahzad hit an incredible 74* from 16 balls and English players like Bairstow and Hales were close to scoring hundreds in just 10 overs.
If they bring that attitude back to the Blast things could get interesting very quickly. I'm not sure if Cook will be able to keep up with that. Mind you, I'm not sure any other Essex player can either so if that happens we're probably screwed anyway!
Also where does Cook fit into the team? Delport will presumably open. The one success from last year's T20 was Varun Chopra do you move him from opening? Do you bat Cook in the middle order?