I don't know about you, but I would have personally preferred to see honest comments from your 'Average Joe DMs' than established authors (one of which also happens to be a freelancer working for WoTC). They probably thought that Ari and John have more "street credibility" among the gamer community, but as an "average" DM myself, I would have liked to see opinions from more "non-biased" and hard-working fellow gamers. Is it that hard to tell them that "You may post info about these details but do not reply to any questions"? And these guys who run games every week or so couldn't "handle the pressure"? :\
Anyway, I don't think that Ari is as "non-biased" as he may want to appear -- if he had remained silent or expressed negative opinions about 4E, I think it might have made reflected on his future assignments (or that may be what he feared?). I'm not saying that it would have, or that he thought it would, but so far I've not seen WoTC designers (except Rich Baker) handling criticism (even when it has been expressed in a polite and constructive form) very well.
I also have an issue with overly-positive reviews which seem to follow a very strict and "codified" format: "It's awesome, it's cool, it's faster, it's better and I'll never play 3E ever again!". I've seen such claims in every designer blog so far, and I already *BELIEVE* that "my head will explode with all the awesomeness" (as Logan Bonner, I think, said in 'Races and Classes'). Why not tone down the "awesomeness factor"? Why not just say that you and your group liked it because of X and Y and Z, without going into mechanical details?
And what's with the "fun and exciting non-combat stuff each class will have"? We were more or less *promised* that 4E would have them. Will it just be house-ruled or handled case-by-case (as we did with the Secondary Skills)? And will there be rules for the "Social Encounters/Combat"? I *think* I saw an interview in which it was said that they couldn't make it work, so it's not going to be in PHB or DMG? I might be wrong, thought. And didn't Ari and/or John remark that only the "essential mechanics" (i.e. combat) are presented in the game, and they had to house-rule stuff (checks) on the fly?
This is a very essential issue for me, as my group had concentrated more and more on "non-combat stuff" since 3E came out (and had rules for things like Crafting and running your own guild or shop). Funnily enough, we never thought about how much a character with 'Gemcutting'-NWP would make per month, but as we've now gotten used to having mechanics for 'fluffy' skills such as this (and making a living with these skills outside adventuring), I think my players will not be satisfied if it feels just like a "hobby" without any impact in the game. Besides, how many such "freebies" can your characters have? How much control do the players have over them? Is it valid to state that your character is a 'Master Armorer' at 1st level, if you can work that into your backstory? Or even the best in the world? And how much GPs will such a talented individual make per month? Or can a Master Armorer craft a full-plate at 1st level? Of course, a DM can always say that "Your Master Jeweler-skill/trait gains you X number of GPs per month, period." or that "You can only be a 'generic' Jeweler or an apprentice", but my players would feel cheated.
I can house-rule stuff on the fly, too, but how about newbie DMs without any points of reference? And I could always just refer to the 3E rules (e.g. concerning Craft and other 'fluffy' skills if my players want their characters to have them), but that would probably make me feel that 4E is "flawed" for my group's purposes.