Judgment underperformed because of a mixture of factors, but the gameplay formula is not one of them.
I agree with everything else you wrote except this. Gameplay formula was without a doubt a factor why Judgment underperformed. People who bought it stopped playing it after a short while and I listed some of the reasons in my previous post. Gears 3 had more unique users playing than Judgment not long after Judgments launch, game didin't have any legs without popular multiplayer.
I agree with LudicrousSpeed tho, for me Judgment was worth it for Overrun alone. I played the hell out of that mode and I'll gladly play it again with BC granted there's enough people online. But of course since Epic made the online portion of the game, I don't know if Chmielarz deserves any credit from this innovation :P If I'm not mistaken he works with People Can Fly who made the campaign.