I strongly believe that W is smarter than people think, smarter than most of his critics, and smarter than Gabbard, and that being govenor of Texas is good preparation for being president. He was a terrible president, but I blame that more on the general rot of the GOP than on him being unusually poorly prepared, incapable, or unready. That is, what made him bad was just doing the same kinds of shit that any Republican president would have done in that era. Contrast that with Trump, who is doing the same dumb things that Bush did, but is also grossly incompetent and morally and temperamentally unfit.
And I think you're misreading me on my view of qualification if you think it's too narrow. I pointed out Obama's books (and their success and quality) as being qualifying. If Taylor Swift wanted to run for office in 10 years, I'd think that her songwriting and business success would make her at least an interesting candidate (not for president, right away, though, but it would count toward my regard of her as a later presidential candidate). Not narrow at all. The problem with Gabbard is not that her credentials are unconventional. They're conventional but unimpressive, and nothing about her makes up for it. I could overlook her not excelling as a student if she demonstrated expertise in something afterward. I could overlook her lack of gov't experience if she had an impressive career in the private sector before entering gov't. Etc. Give me *something*, though. Some reason to think that you'd be good in the most important job in the world.