SteveC
Doing the best imitation of myself
Good question. For me I like to divide the game into the rules and the adventures/setting books.Which late edition products are you referring to? (I am still so enamoured with, inter alia, the Neverwinter Campaign Setting that I may be missing some dogs! )
For me, 4E was the only edition of D&D where the designers actually got better as the edition's life extended. You can see this particularly in the adventures where 4E began with rubbish authored by Mike Mearls and Bruce Cordell (I can still remember when the latter actually wrote good adventures) to new classics such as Reavers of Harkenwold and Madness at Gardmore Abbey. And the few post-Essentials splat books were generally well-received, other than Heroes of Shadow which had Mike Mearls as its lead designer. (I must admit, though, as someone who stays in the levels 1-12 range in my games, I quite like Heroes of Shadow.)
I'd say that as the edition went on, the quality of the adventures got much better (but, you might argue, it was hard to go anywhere but up). At the same time, about the time they announced the Essentials series, about the time they cancelled all of the books I was looking for, the rules quality went way down.
Obviously this is my opinion only, and I mean nothing negative towards the folks who worked on some of them ... but I just thought they were awful.
I remember wondering why the Essentials books were released in a format where you were paying for redundant material, and the class designs started to show individual tables for level advancement again.
And then the Heroes of Series started to show up and it was clear that there were a new vision behind the rules, someone who either didn't like the earlier designs, or really wasn't involved enough with them to begin with.
I know that's by no means a universal assessment, but it is mine.
Now as far as adventures go, I really enjoyed some of them. The last product I remember buying as a DM was Murder at Gardmore Abbey, and my group had a lot of fun with that. Similarly, I got some real use out of the Neverwinter book (as you mention).
I don't mean to harp on it, but I think the second half of the 4E lifespan was a sort of self-fulfilling prophesy where books weren't selling, so they changed them up or simply stopped releasing product. Of course that meant a reboot was coming... I'm just shocked that WotC was content to basically stop making product for a couple of years.