Anyone in 3E could have made a 4E stat block just by not caring quite as much about getting it 'right'. Rules were made to be broken, and they were. As far as I can tell, 4E simply gives you permission. Maybe it's the 1E DM in me, but I never thought I needed it. If I just wanted a monster for a fight, getting its skill points exactly right is pretty pointless.
But, I find taking things out or changing things is easier than putting things back in.
As best as I can tell, the 4E block is just a comprimise between 1E and 3E. It's the Jack of All Trades, master of none approach. It's worked for D&D historically, but I'm guessing that people who are praising how this lets you use monsters right out of the box, probably won't actually do so. The urge to tinker is strong. Especially in those people who complain about how much work there was in getting something 'right' for 3E. Hint: No one forced them to get it exactly right.
Leave off the fluff, confine the monsters to one or two powers each, and you can fit 500 3E monsters in a manual too.
Considering I didn't buy MM's 2-5, I guess I'm not the target audience anyway.