That is your answer, minus the "best at what I do". I've done 100's, maybe closer to 1,000 interviews, and if someone said they're the best at what they do, I'd likely disqualify them.
Sucks to hear Cardinal didn't get back to you, I know when we were emailing it sounded good.
I just switched jobs and when they asked me why I was looking, I indicated I was passively looking because 5 years at my current company I'd be at "point X" and 5 years with this company I'd be at "point Y". That was the truth, but I also couldn't stand to be in the same zip code as my boss. Miserable, miserable fuck that tried to pass her pathetic life down to me. But the main reason I left was because of growth potential. A perfectly acceptable answer.
If you don't have any questions at the end, then you don't have any questions. BUT, as the other person said, I'd recommend asking about the culture of the company and the environment, and I ALWAYS ask what their expectations for the role are moving forward, and I always ask about the strengths and weaknesses of the state of the department.
Another tip: Know you who're interviewing with. I researched all 6 people I interviewed with prior to going in. When I told one of them I see they went to my alma mater, they looked like they were going to splooge on the spot. People respect it when you take the time to research. LinkedIn is your friend!