I think that Dumbledore and Harry were too quick to conclude that the Dementor could just be used as a distraction
True, and somewhat understated. Dumbledore defeated Grindelwald and led a hard fought defence against Voldemort and his death eaters. Why on earth does he need to call in an eleven year old with magic cold/angry powers just to come up with the thought 'maybe it is a distraction'?
This Dumbledore has been crippled to beyond all recognition.
Two possibilities:
Dumbledore has been too busy to step back and think about the situation creatively.
Dumbledore is making up a reason to invite Harry Potter into his office to (a) get his report on Lucius Malfoy, (b) warn Harry about the Dementor coming onto campus, (c) encourage Harry to practice his cunning outside the formalized exercises of Quirrell's armies, (d) lend credence in Harry's eyes to his suspicions of Quirrell by revealing that Quirrell is acting suspiciously, (e) query Harry about Voldemort.
I do not find either entirely implausible.
ETA: There is now a third thread, so send new comments there.
Since the first thread has exceeded 500 comments, it seems time for a new one, with Eliezer's just-posted Chapter 33 & 34 to kick things off.
From previous post: