Spoilers for The Harriet Dinner II under the cut.
I've just finished watching "The Harriet Dinner II", and my opinion is - he's really back now. We're going to be left breathless a lot more often, and there aren't going to be any more episodes where we can seriously debate whether he knows what he's doing. And the dialogue is just sparkling, even when it's serious. IMO this three-parter is already better than Sports Night at its best.
Every single relationship he was exploring in this arc was complex and unsettling, all arguments had lies and truth on both sides, and almost none of the pain or the joy came primarily from the events of that night, but from the backstory he's meticulously built up since he worked out where he was taking this (in months to come I'm sure we'll debate when that was).
The relationships are also artfully balanced one against the other, so that we're not just looking into one at a time, but also one reflected in another. Jordan and Danny are entering bliss (and hard work) just as Matt (and maybe Harriet) are entering the Valley of the Damned (and maybe self-indulgent), while Tom and Lucy are holding the normalised ground in the middle. Kim's "cute" is like Matt's "cute" - potentially lethal, and you're not sure how conscious that is. Simon and Darius and Jack and Mr Ziaou (have I spelt that correctly?) are both hoping to smooth power struggles that are still potentially volcanic.
We don't know yet what the relationship between Jack, Jordan and Hallie really is, but it might be the same as the parable of the snake, the ferret and the coyote. (Sorkin loves those "hole" parables! Would anyone like to write a disssertation on the meaning of this one? Particularly as the smashing of the floor at the end resonates into the Matt/Harriet relationship?)
I'll probably be back to rave about more things when I've seen it again. But, oh yes, I also really love these people now.
My guess is that, now he's reached this level of confidence, the political framework he started with will slowly bleed back in, and will work better because he's got a really strong human framework to set it in, and because the characters matter so much more to us now.