That's not really what I said. What I said was: these d20 designers all have independent, proven track records as professional game designers AND as veteran gamers. From that hard cold evidence I conclude they would do a good job if they decided to unite to create a SRD-based fantasy gaming ruleset. And if they could find something they all agree on, I guarantee it would be good. I think the Trolls did a good job all by themselves with respect to C&C design. I'm not familiar with Monte Cook's rule stuff, but I know those things have been very well received in the d20 community. I have looked at Blue Rose and think it's good and interesting. If, hypothetically, all those folks came up with something, I KNOW it would be good.
I don't know who all is involved in 4E. Mike Mearls I know mostly from his design work for Necro and Goodman, and he's just fine. Bill Slaviscek wrote d6 Star Wars, which is a very, very fine game.
However, the gods on Olympus at 1,000 keyboards can't write a ruleset in a week much less playtest it. Clark explained that better than I can, but I'm sure there are enough software designers to know about marketing-driven timelines. Their work will get emailed to someone who emails it to someone who reports to Hasbro, who makes cheesy marketing videos and negotiates Pirates of the Caribbean tie-ins. I'm not necessarily bashing Hasbro, it's just a publicly-traded corporation and that means the officers and directors are legally required to make a profit for shareholders. Short playtesting means speed to market, and that means more revenue sooner.