As I re-read my response and your reply, I'm hoping we're talking about the same things.
When I say hiking or skinning a *lot*, I guess I'm referring to situations where you might be hiking (generic term for walking, booting, skinning, etc) for periods of as much as three or four hours (or more) a day. That's actually quite a lot of hiking during a day for most backcountry outings, and that much time or more is where you would probably really start to see the improvements in comfort and fatigue (because of lighter weight and easier flex) that an AT boot would offer you.
When I say yo-yo'ing or resort backcountry, I might typically only be hiking for a total time of an hour or two a day. In *those* situations, I can get along just fine with my alpine boots.
Think of it as a continuum along which you need to locate yourself. If you do mostly shorter hikes, an alpine boot won't kill your feet too badly on the hike and will ski better when you're going downhill. If you do mostly longer hikes, an AT boot will be much more comfortable and won't feel quite as much like dead wood at the ends of your legs, but will still ski well when you're going down.
Next, you may have interpreted my reference to the Denali a little differently than I meant it. The Denali is a great boot for downhill backcountry skiing and is a bit better for hiking than a traditional alpine boot, but most "hikers" (the ones on the longer hike side of that continuum) find the Denali fairly similar to alpine boots. The more middle-line AT boots, like my Scarpa Lazers, are way more comfortable for hiking. They don't offer quite as much pure control in downhill skiing mode, but *most* of the time you're skiing pretty good conditions and the boots like the Lazer offer more than enough performance to handle the conditions. I'm also convinced they make you a better skier because they encourage a more centered, balanced stance and style.
Lastly, your comment about skinning vs. postholing in the context of alpine boots vs. AT boots makes me want to add a slight clarification. The Fritschi and Silvretta bindings do allow you to use either an alpine boot or an AT boot. So, if you put Fritschis on your skis, you can use your skins with either alpine boots or AT boots or both.