Le slippery slopes. I'm probably not the most appropriate person to respond to this, but it admittedly intrigued me, in a somewhat negative way.
Those examples and comparisons are terrible, so to speak. I mean, there's a far more justified reason the two obese Special Walls are being suspect banned this way over everything else you've listed, and evidenced in practice as well. Removing Heracross and Ursaring, for instance, unless they fall under the offensive characteristic suddenly is not justified at all, apart from the stupid idea of "creating more variety for stuff like Machamp, and all." I'm pretty sure it's logical to say that physical attacking is not stagnant nor is it stagnating anything -- in a significant way, at least. Variety in physical attacking still exists, whereas Bliss/Lax on the other hand display stagnation not only on the Special Attacking end but also some other minor things as well; heck, it mainly stagnates the usage of special walls. This test doesn't approach the standard policy of "fall under characteristics", but, well, just check some text walls in this thread explaining why.
"A ban does not result in a variety boom. A ban results in a shuffle, etc."
When something that is stagnating the metagame is banned, the variety will change, inevitably, if not increase. Whether or not this will be true to the case in regards to the Blissey/Snorlax ban is unsure since we've not tested it yet, but it's what the council has come up with under the observation of the solo Bliss and the Bliss/Lax metas. And the council, with apologies for this presumptuous statement, perhaps believes that the near-fail safe ability to counter or check Special Attackers of Blissey and Snorlax, in tandem with a lot of other things they can do, are stagnating the metagame. As much as it's possibly false as it may turn out in practice, I believe it's true to word that special walling will no longer be failsafe and the variety of other special cushions will have to be used; people will have to think and plan instead of slapping an irreplaceable wall on their team which is the "variety" a healthy metagame desirably possesses.
As for your final paragraph...that's what the council's been focusing on, to be fair. There was never any "characteristic ban" in this discussion to begin with, so not sure how you're pulling that out of your hat.
EDIT: Two ninjas, damn.