Thanks, Frederick. It's better to try and occasionally err on the way to improvement than to sit back and b*tch about the status quo... Still, I'm a little bit intrigued by the idea that there's at least some tension between what you call "WP's native behavior" and what I'd call "optimization".
Obviously there's stuff far outside WP's grasp (i.e. the rest running on the servers) but it's a bit of a troubling realization that performance is treated almost as an afterthought on self-hosted WP sites. It'd be nice if there were an extra quality label available for plugins and themes out there - somewhat like the energy impact label on electric household items - so as to point out the severity of the performance hit resulting from installing and using a given plugin and/or bad known interactions ("bad combos") with other plugins. I guess that's a noble pipe dream, though.
Of course, you as the developer of W3TC are just looking at the mess, and your effort in bumping up performance for us poor souls is still enormously appreciated. But as undoubtedly frustrating as it is to read variations of "your plugin doesn't work" you have at least my word appreciating your effort, Frederick.
So: thanks again.