Here's a guy who installed a Hobie Mirage unit in a wood kayak.
It's All in the Legs
I think the leg power thing has some merit. You'd want to be able to use the paddle too, and not give up a sleek, efficient hull or a low CG.
When you get caught out after the wind and chop have picked up, especially if you're paddling against a stiff wind, it can be hard to make headway. A 10 mile crossing can take several hours. Weak paddlers need towing, people start pissing in their boats, the whole thing is not fun. Having a leg option would be nice.