I was going to respond in my most recent Skill Challenge thread, but then I remembered that this one was here.
So I've read the most recent portion of that "Let's Read" thread and he has (a) analyzed the SC section and (b) provided examples of its usage in you guys' play.
I must say. I find it terrifically amusing to see a self-avowed grognard/old-school type groking the system right off, espousing its virtues generally (while being aware of its shortcomings), and giving specific commentary that fundamentally mirrors what several of us on these boards have been saying for years (about its proper application and the indie GMing best practices that underwrites its best usage)!
This is with no prodding from any of us that might bias him! He came to those conclusions on his own entirely. The source of the deep division on the (dis)functionality and (in)coherence of SCs has often baffled me. I do think I see some strain of shared experience and corresponding mental framework on my side of the fence (old school grognards who also have a lot of exposure in and appreciation for GMing conflict-driven, scene-based indie games). I wonder if he is another data point to that end.
Part of it, frankly, is Keehnelf's ability to take a step back and tell himself, "This is a new game, with a new goal and purpose. What's that like in action? Maybe it could be fun." He doesn't expect every D&D to be the same D&D--just that it have...plausible similarity, I guess. And with our game, he's specifically pushing the system in the directions that it most thoroughly encourages: refluff things, customize your monsters the way you want them to work, have high-action high-drama scenes, be open to the strange and the crazy if your players are, etc.
I definitely feel like his experience with far, far "looser" systems is a huge boon for being a first-time 4e DM; specifically, the PbtA games. Despite being mechanically as different as night and day, 4e captures a similar result. In fact, they may not actually be
that much different! Both games have clear, overt rules the players can see and leverage. Both have important guidelines for the DM--but specific advice to disregard those guidelines when it makes for a better game. Both put an emphasis on party diversity to avoid issues during play (DW classes tend to have one Core Thing, so two Fighters can be kind of dull; 4e classes have their roles, and having the four bases covered is Pretty Important). Sure, the specific mechanical implementation is different, but I mean, 4e's keywords are effectively identical to DW's tags, in that they point to specific game-rule elements and are often used for balance of some kind (consider the number of DW classes that have the "you ignore the Clumsy tag on armor you wear" feature!)
And, lest I pain an inaccurate picture: none of this is to say that he's jettisoned his old sensibilities. They're absolutely still there, and he's had some beefs with the way the book authors casually present highly debatable stuff as standard or even expected (e.g. "all that non-combat stuff is a nice break between bouts of FUN" and such claptrap). It's just that he can evaluate things from within their new context--as long as they don't disparage, intentionally or unintentionally, the contexts he's coming from. Because of that, I think his focus has been more on, "Wow, this is pretty solid for its goals!" rather than "Wow, this is NOT the game I expected to play!" And that difference--pleased at a thing being good for its particular flavor, rather than bothered for it not having the "right" flavor--is what has made everything else possible.
As a result, he's giving 4e a no-holds-barred, fully on-board run, and it's going great, at least for me. If I had stumbled on his recruitment threads without knowing the context behind the game, I don't think I'd ever know that he is a self-professed grognard coming into 4e for the first time. Even his first attempt at a Skill Challenge was solid (though he's also improved, rapidly); his encounters are varied and challenging, and thus far we've only had one (the very first of the campaign, for me at least--I joined up a session late) that didn't have some kind of altered or tweaked victory condition besides "kill all the things dead." He's eminently comfortable reskinning, tweaking, and adapting monsters to fit the context, like with the mainframe/turret fight (I don't remember the details, but he explained them to us after). Sometimes, little rules minutia slip past, e.g. he wasn't sure whether forced movement considers difficult terrain (it doesn't, but blocking terrain e.g. solid walls, and hindering terrain e.g. lava pools, do), but that's hardly surprising even for a longtime GM.