[evilstark]

"What is the one thing an engineer could do that would make a huge difference in where we are trying to take this thing?"

This question

-- a) gives him an opportunity to tell you exactly where we are trying to take this thing,

-- b) shows you what he thinks is the value of engineering talent, and

-- c) gives you a good picture of what exactly you should be focused on if you want to really succeed here.

Go get em!