In fact, I go back and forth about how maybe if we'd known a bit more about the backstage goings-on, could they have found a way to make it even more powerful? Because there's shock value in the whole reveal that Chuck is complicit, but that only works if we're in B's POV, which we basically are. If you're a Chuck fan, waiting for Chuck to be involved in this episode, it's both heartbreaking and a rabbit from a hat, because of that moment when S tells him B's disappeared and he runs upstairs and finds the box, and acts like it's a shock even though the only shock is that she went through with it, which is what he wanted and what he didn't want, too.
It's nice how this show has always taken the post-DVR road of making the show, non-pejoratively, into a sort of video game: Play an episode once as Blair, and it's shocking and heartbreaking. Play it again as Chuck, knowing what we know, and it gets all the darker and sadder and nastier. Usually we get that both-ways twist with Blair, because she's having emotional shit that she doesn't even know about until the end of the episode, and then looking back every whackadoo thing she does makes total sense. And always with Lily -- and sometimes her mother, in a more Blair fashion -- because Lily's the only actual liar on the entire show.
But the Chuck/Blair relationship is so important to the show, and the insaner fans, that they generally have to play it straight, to the point of having them both say ridiculously face-front literal things all the time. To their detriment, obviously. So I think a lot of this shock value -- which turned it seems equal numbers of people off, and on -- comes out of our trust of Chuck as a reliable narrator... Just as Blair does. The reveal feels like a real reveal, a Pete Fairman murder confession unspooling, which is something this show has been lacking.
Back from break, Blair gives him a strict no ("I'd rather spend the night with the Marquis De Sade. And yes, I know he's dead") so Jack starts applying the pressure points Chuck gave him: "I'm surprised... Knowing how attached Chuck is to his hotel, what it means to him. I thought you really cared for him... Chuck opened his heart to you, and now his future lies in your hands... Well, not your hands, exactly. But you could fix this. He would never have to know." And that's... The recipe to Blair. If he'd somehow been able to throw in a reference to her Serena loyalties, that would be literally everything that makes Blair, Blair.