I'd never want to besmirch the fine fellow's record/legacy, but I do have similar disagreements here.
I know this is probably crazy (and sounding brutally hypocritical from me), but I think a lot of this is a bit too analytically steeped.
4e's basic principles and general noncombat conflict resolution techniques are sufficient to handle the workload of Social Skill Challenges:
1) Go to the action. In this case that is conflict-charged social disputes with high stakes.
2) Identify any and all potential obstacles to the PCs' goals, introduce them as the fiction and mechanics warrant, and play them to the hilt. Social obstacles aren't just one NPC's obstinance. It can be a myriad of things beyond that (an as-of-yet unidentified need that requires fulfilling, their relationships to people/places/ideology, who/what is ultimately pulling the strings, the situation's temporal or spatial dynamics, the situation's greater context)
3) Change the situation. Success means to introduce a new obstacle but keep the urgency status quo. Failure means to either introduce a new obstacle or significantly escalate the threat/opposition of an existing obstacle, but always up the urgency/desperation.
4) Failure is not an endpoint. Ultimately, if the PCs lose the challenge, interesting stuff needs to happen. The trajectory of play might change, but the action cannot stall (certain options might close, but a new decision-tree emerges).
Personally, I don't think the following is good advice:
a) Tailor the challenge to the group's build dynamics. Now definitely consider the prior fiction and identify the PCs' thematic interests (typically signalled by build), but don't artificially constrain the obstacles you introduce because of group build dynamics. Consider how stale the combat analogue would be (eg never use Obstacle and Y-axis protected Artillery because the group isn't synergized for mobility or ranged attacks).
b) Belaboring the action by excessive dialogue/expository monologue.
c) Constructing a Skill Challenge in advance. I know this is a thing, but I don't feel it is particularly helpful to current or burgeoning GMs. Learn to improvise better. Follow your principles. Practice your craft/techniques. Prep light but more nimbly/functional (perhaps always have a set of flashcards with coherent and broad obstacles for various conflicts - Social (including things like Exorcisms) and all the various Exploration related ones; Chases, Perilous Journeys, Infiltration/Intel Gathering Operations, etc.
More prep is never the better answer because it isn't as functional for actual play; you may never use that material, you'll be more inclined to deploy Force to ensure that material sees play, you're increasing your out-of-game overhead just to play at all, and (as importantly as the rest) you're either atrophying your current ability to be nimble/improvise during play or you aren't growing it.
Seems like we're in close agreement.
I picked out of this one possible innovation that I'm pretty interested in, so its going into my "ideas and notes" folder. That's making up a 'deck' (could be some charts, though cards seem handy and quick here) of stock factors to add to social challenges. They could take a very general form, so maybe a table something like: (this is just a quick example, not an actual recommedation)
1. Possession - someone or something is possessed. This could be a principle NPC, a relative, an advisor, or even someone in the party!
2. Debt - someone is in debt to someone else. This consideration is factoring into their decision making. It may or may not be obvious or well-known.
3. Spiritual Obligation - someone has an obligation, to perform a ritual, make a sacrifice, refrain from some action, etc which is factoring into their decision making.
4. Ambition - Someone in this situation is dedicated to achieving some difficult goal, such as amassing a fortune, gaining political power, acquiring a new position or office, etc.
5. Prophesy - Some sort of prediction has been made which affects the various participants in the situation and colors their decisions.
6. Enmity - someone hates someone else and this has some effect on the situation.
Now, assuming you had a bit more extensive and perhaps nuanced collection of 'situation cards' like this you could, as the GM, play out a couple of them and quickly generate an interesting scenario around them as needed. You could also do the same thing ahead of time, or at least use the list as a seed for embellishing these scenarios.
A similar technique could work with other sorts of challenge situations. A chase, for example, could easily be quickly embellished with a series of cards that generate obstacles and opportunities. When stated in fairly general terms they should be applicable to most similar situations.
It might be a bit harder to come up with a set for say "general physical challenges" though some thought may still generate a reasonably useful list.
You might also want to provide for a number of variations of each of these for each type of scenario. So there could be curses, prophesies, vendettas, possessions, obligations, etc etc etc drilled down to a couple levels deep. Unusual events could also be factored in, which would be pretty reasonable for a challenge that might span over a period of time (negotiations go on for a week, then there's a peasant uprising and the various parties are suddenly forced to cooperate, which changes the dynamics of the situation and opens up new skills and such).
The primary goal of all of this obviously is to broaden the challenge and give it additional depth so that it is likely to engage more characters and become more dynamic and produce more opportunities for the players to either increase the stakes or cut their losses.
