I've been working on solutions to a previously-described problem, and come upon a half-solution that makes things potentially quite a lot worse for those of us with 2.1+.
My problem was that I couldn't get a custom page ("Schedule") with a custom template ("schedule.php") to load The Loop. I discovered under Options --> Reading that if I changed a setting I'd previously established, for the Front Page to display a static page, that if I set the "Posts Page" to "Schedule", all of a sudden my Schedule Page was using The Loop -- though it wasn't using it with the conditions set by schedule.php, suggesting that it was now ignoring its default template and simply using index.php.
So, temporarily, I switched the "Front Page Displays" setting to "Your Latest Posts" so that there's no specified "Posts Page". Well, now the Schedule Page and schedule.php once again won't load The Loop, only content I create in the Schedule Page (should I choose to do so).
It appears, given this and other testing of code that I've done on this problem, that 2.1+ limits the number of Pages that can load to The Loop to 1.
Can this really be so? Or are there some new ways of loading The Loop for a custom Page and Template in 2.1+?