Steve didn't say why he left Samsung, just that he wanted to do "something new". On his way out, he had some thoughts on the Galaxy S 4. Like many of us, he was not impressed with the design of the hardware, but said that the specs "blows the competition out of the water." He also said there were some features with "potential", like the IR blaster, and the touchless controls.
Overall, he was impressed with the features added, but does admit that he always disables Smart Scroll. TouchWiz did not get much love from Mr. Kondik though. The best he could say about TouchWiz was that it had gotten more consistent. Although, right after saying that, he said that different parts of the OS feel "mismatched", which seems to contradict the consistency part of things. He ended up taking a pretty big swing at TouchWiz, going so far as to say "it feels like it has been sent a few years back in time to the Froyo days." Ouch.
We're looking forward to seeing what Mr. Kondik gets up to not that he's leaving Samsung, and we'll keep watch.