This will be wildly context dependent. I stepped down (or perhaps more correctly, out -- I left the company) and was happier as I transitioned to a job I was more suited to. I suspect whether moving out of the CTO role will make you happier depends on how able you are to give up technical/architectural ownership to someone else. In my case, it was easy -- I was done and had no interest in the product anymore. However, if you still care about decisions, I'd imagine you're setting yourself up for a different kind of angst: seeing your replacement do things "the wrong way" and not being able to fix it. Of course, YMMV.
