I agree with you that the best QA testers are usually the people overqualified for it. I disagree that most of the fun and pay is in CS. I've spent over a decade in QA -- moving from grunt entry-level tester to lead to manager -- and not only is the pay commensurate with talent and experience (in the right company, of course) but the fun is why I stay in this job. (Although I do have less fun managing than I did testing...)
When I look for a good QA tester, I want someone who could be a developer, but would rather break things than fix things. I want someone who looks at code not as something beautiful to be admired, but as a house of cards to be knocked down, and those who understand the underlying structure are better at knocking down that house of cards. Anyone (well, almost anyone) can follow a rudimentary manual test and click where they're told to click. It takes someone else to think outside of the box, as odious as that phrase is, and attack a site or an application beyond the requirements.
Bad tester: "Huh, when I click this button, it takes a long time for the results to return. At least I can still click around..."
Better tester: "Huh, that's asynch, and I know from the architecture diagram that I can then do X and Y, and oh look, I brought down the site."
As I hinted at in another comment above: the developer builds the sand castle, and QA kicks it down then waits for the developer to build a better sand castle.