Good ending to the series, just watched it. It was a really good series. It really didn't change THAT much in quality. Usually as series drag on year over year they kind of get more outlandish and over the top with cheap humor (Simpsons.) This was one of the rare times it didn't. It kind went in the opposite direction, I dunno, it had a different feel than earlier in the series.
Kinda like supporting characters and the more silly situations got phased out. I can't remember the last time it seemed like Connie had an episode where she was involved, seemed really odd she used to be in all the episodes hanging out with Bobby, being his girlfriend and that was a good plotline, and then she just kind of disappeared. Then you had Hank and his dad, LuAnne and her being a dumb blonde, Dale's crazy paranoid plots and stuff. It didn't get more outlandish, feels like it got more quiet and normal I guess. Kinda like if you said about 3 years ago that KOTH series ended and this is all the stuff that went on in their every day life since that point.
I think it was a show at its best when Hank was put in really weird, awkward situations to him. The whole plot with Debbie accidentally getting killed and Buck trying to set him up and Hank accidentally smoked weed.

Or the episode where Hank unknowingly comes off as a pimp when one of Peggie's friends turns out to be a hooker.

I dunno, it kind of went from that silly awkward situations to more everyday life episodes of Hank getting his friend out of a jam, or bonding with Bobby, or something along those lines. I don't think that was KOTH at its best though, although by no means was it bad. It went out at series end better than 90% of shows have.