I don't think it's so much the fluff versus the crunch that turned me off from the Manual of the Planes, but the lack of usable details. Once I read the section on the planes in the
DMG and the Forgotten Realms Campaign Book, I felt like I had a good handle on how they work and what they're like generally. What I wanted, and expected, were more table-usable details. The way it's written now in MotP, I have to basically write all of that myself. Granted, many of us enjoy writing that stuff ourselves, but if that's the case, i don't really need the MotP to do that - I have enough of the gist in the
DMG.
Coming up with descriptions of the planes for my players is easy. I've read so many fantasy novels and played enough games to piece together a good planar model. Building hazards, creatures, and encounters that are balanced and capture the atmosphere of a plane is hard. Even some samples would have gone a long way to help me along. I expected Wizards to do more heavy lifting with this one.