I'm kind of with you on much of this. As I said, I have only been watching this show over the last four years or so, having binge-watched everything up to that point, therefore I understand that I don't have nearly the sort of investment in it as those who have watched it, year by year (with, no doubt, lots of repeat viewings during the off seasons). I guess in a way I see myself, in this forum, at least, as the casual viewer, who is just there for the entertainment, and all the pretty that is Dean, without getting caught up in all the drama of exactly who the characters are and whether the various writers are true to them; I just don't have enough background with the show to really worry about it, so may be more representative of possibly a good chunk of the audience.
I did mostly enjoy this episode, and the old characters we saw turning up. Yes, it does seem re-vamped overall as something at least a bit different from the original show, but, to me, at least, it doesn't feel jarring as much as a set-up to what I hope (and it's nothing more than a hope, given how many shows have had truly dismal attempts to tie things up) to some sort of ending which will encompass various elements from past seasons. I'm not sure there's a way, at this point, to come up with something truly satisfying - it's been something of a mess for so long - but I'll settle for something that feels like an ending, and preferably something which can make me feel good.