That's it! You've nailed it! The uncanny thing about Bloom's Falstaff-worship is that the character has no shame, and Bloom has no qualms about that fact. In fact, Falstaff's shamelessness is the key to his greatness, and greatness is pretty much the only quality that matters to Bloom. Falstaff is so large, so free, so wise--an ex-warrior who has seen the folly of warfare and personal ambition and chosen debauchery instead--he cannot be contained by shame. Does he murder, does he thieve, does he harm his fellow carousers with his wit? Yes, but let us not concern ourselves with such quibbles, because what's important is the magnitude of his charisma.
In short, he's an Uebermensch. Is Bloom's focus on him self-aggrandizing? Yes, but it's justified. Bloom's indisputable power as a Shakespearean critic lies in his ability to do two things: 1) He shows you how one character's perspective usurps a play, sucking the authority out of every other character's perspective, and 2) He makes it hard for you to see the plays any other way. Falstaff usurps Hal in the Henry IV plays; Hamlet and Lear dominate their plays; skeptical Rosalind reigns in As You Like It; Cleopatra runs away with Antony and Cleopatra; Macbeth looms over Macbeth, to our acute discomfort, since his inner life is a nightmare beyond hell. And Bloom towers over them all, as well as over all the other critics, because it is he who reveals unto us their greatness.
You pointed out the problem with this in your first line in this Book Club: Shakespeare's plays contain everything. They're theater, and that demands a different way of reading than lyrical poetry, which is where Bloom's real expertise lies. (He may be the greatest reader of the Romantic canon in this century.) Bloom's dramatic consciousness is really lyrical consciousness. It's entirely mental, entirely solipsistic--it involves one extraordinary mind grappling with its predecessors, its contemporaries or surroundings be damned. Insofar as Bloom allows Shakespeare's characters to be theatrical, it is only in their unhappy realization that they're forced to play a role in the world, to have truck with lesser mortals.
But theater's great virtue is that it represents not individuals but a community; the people who inhabit it cannot escape their world. Characters exist in relation to other characters, not just to themselves. This makes theater the ultimate ironic genre, in that it prohibits any one take on the world from definitively trumping the others. There's always another perspective to entertain. Is Falstaff completely beyond criticism, as Bloom claims? Is everyone who fails to enthuse about him as loudly as Bloom does somehow diminished in their humanity? Or is it that Bloom is too blinded by his own passionate (and charismatic) identification with him to see the claims made by other characters? If I were a man like Bloom, whose claim to greatness lies in itself--that is, in his largeness of mind and imagination--it might be hard to contemplate the possibility that Falstaff may not be irreproachable, that greatness may not be all. Other qualities may matter too--compassion, or, as you say, the ability to feel shame and change.
In fact, there's something not only inhumane but inhuman about Bloom's insistence on charisma and power at the expense of every other attribute. And this, to me, is the fundamental irony of the book. Bloom means to demonstrate that Shakespeare invented our notion of what is human, and yet Bloom's version of Shakespeare's characters is anything but human. These aren't personalities; they're Nietzschean and Gnostic principles made flesh. What else are we to make of this passage describing Hamlet?
"Yet we worship (in a secular way) this all-but-infinite consciousness; what we call Romanticism was engendered by Hamlet, though it required two centuries before the prince's self--consciousness became universally prevalent, and almost a third century before Nietzsche insisted that Hamlet possessed 'true knowledge, an insight into the horrible truth,' which is the abyss between mundane reality and the Dionysian rapture of endless consciousness."
That it is stunningly interesting, powerful and uncanny, even beyond brilliant, I will readily admit. I will ponder it whenever I see Hamlet, or encounter one of his many literary progeny. But even if it's true, does this account of Hamlet's inner life obviate the virtues of others' experience? Does the unrequited love of Ophelia and Gertude mean nothing? Can we not ask what we're to make of the fact that Hamlet cavalierly killed Rosenkranz and Guildenstern? Or must we all stop speaking and thinking and bow down to greatness, to Hamlet and to Falstaff and to Bloom?