The most interesting part to me was this quote:
"Wizards' design philosophy and mine also started to head in different directions around that time. I value a single, uncompromised vision, and they value teamwork. (That's me trying to be fair to their point of view.)"
Perhaps this is only interesting to me since I work here, but it does point to a major shift WotC has gone through in making D&D. The creation of the development team was a huge change, and recently the mechanical design team was separated out, making the process even more group-focused.
Personally, I'm all for this approach. I think we turn out better design when we have more people bringing ideas to the table. In a game like D&D, where there are so many different approaches to playing, we need people with different perspectives and play styles to guarantee that everybody who picks up that book finds something they can get excited about.
That's not to say the "single, uncompromised vision" approach isn't also valid. Would a product like Ptolus be the same if it had been designed by a group? No. Would it have been good? Maybe. I'm guessing it would be tough for a team of, say, six people to really care about such a big book. One person who's invested in the setting is well-suited to that project.
Now, a team working on a set of core books is a different story. When the pieces are broken up into manageable units, you really do care. I care about the rogue and the warlock because I had a hand in making them (and I'm playing them to make sure nobody screws them up

). Rob Heinsoo and Mike Mearls really care about the fighter because they had a major role in deciding how it worked. Everybody working on the book is passionate about something, whether it's the halfling, or the cleric, or feats, or the Athletics skill, or magic items, or DM advice. (You wouldn't believe the debate we had about whether attacking around a corner should take a cover penalty!) The team approach to these books makes sure every nook and cranny of the rules gets the scrutiny it should.
So when Monte says he's trying to be fair to our point of view, I think he's being perfectly fair. I also think teamwork is the right tool for this job, and for most other products we do.