As someone who watches each episode twice the week it airs and has rewatched each season (save 5) a couple of times through now it not only holds up but becomes a richer experience. I think them sticking the landing this season will not just serve as a great final chapter but also enhance the earlier seasons. I think I'll be more interested to revisit Season 5 after the show comes to a close because that is where a good bit of table-setting for the feast that has been Season 6 was done.

To your second point, I agree it is unclear whether Raylan will come out '100% victorious'. I am inclined to think that since the showrunners and writers are obsessed with giving this an ending Leonard would be proud of he will come out alive. Although I'm not particularly well-versed in Leonard's entire bibliography from what I have read, he doesn't seem like killing his protagonists is something he's big on. I could be wrong. But I don't see him coming out completely unscathed or unchanged.