Ruin Explorer
Legend
I suspect differently given the quality work of Monte Cook, but I suppose it's easy to have a scapegoat.
Scapegoat seems a bit much given he actually did what he's accused of, and has basically just said "But I was going to put it back together better than before, honest!". I'd be more inclined to believe him if he outlined his specific intentions as to where it'd have ended up (perhaps he has, but I'm unaware of it). Plus the end result was that the only significant detail on Planescape since then (in the 4E DMG2) relied on the state of play as Monte left it - all the Factions gone, replaced by a few three-letter acronym organisations. If they continue that vision into 5E, well, good grief, what a betrayal of what Zeb Cook did, and what an endorsement of what Monte did. Let's hope they go back to basics on PS, and forget the whole Faction War deal entirely.
Re: quality of work, I'm generally a fan of Monte Cook, but one place he's repeatedly fallen down is in making the detailed bits of settings interesting. Numenera and Diamond Throne both have this a bit. Big picture, they're amazing. Moderate picture, they're cool. But the detailed setting bits? Dull, uninspired, somewhat generic. It's the opposite of Zeb Cook's work, where the close-in work is often fascinatingly complex or unexpected.