Awesome series, and then you get to Season 7..

Season 7 is where is really started going "bad" and almost out of control. By that point the storyline of each character had evolved in such a way that it was absolute mayhem to consolidate them all together and still have a kick-ass series.
Season 7 starts off actually pretty good, he comes out of the loony-bin having had time to work through issues, one expects things to forward in a very positive way. But then Nicki reappears, out of nowhere, they get married 5mins later, and then, Kate suddenly shows up wanting not just to get married but also have a family, hardly anything builds up to this. Then they get married as well, and after discovering the situation with Nicki, she suddenly gets over all her feelings and rejects Drew, not even once mentioning that she realizes it might have had something to do with her timing issues, she clearly doesn't show any sign of being apologetic or even self-aware. She reacts as if it's all Drew's fault, when she was the one at fault for their previous relationship not bearing fruit.
After the Nicki/Kate situation, the rest of the season is mostly just a mess, with little to no linearty through it, and at some point Nicki reappears. This is when I understood it was time to go back to the initial seasons, clearly nothing good could come out of it. When she then takes out her gun, that's a clear sign that there's no turning back to how things used to be, and then she ends up living at his place. The worse comes around when Kate states that she might not be part of the group in the near future and that she's going to Guam. A tragic death would have been so much better. The loss of Kate, and the speed at which it happens, barely over one episode, just killed the whole thing completely. She was the glue that kept them together. The group takes a beating with her departure.

Wick disappears without a trace, Steve as well .. its sad when things can't finish "well". What makes a good story is the start, the middle, but also the ending. If the ending of a story isn't as good as the rest, I find that my appreciation for it suffers greatly. Movies have the same problem, if the ending isn't good, everything that builds up to it becomes almost worthless.

I dont get why the writers behind the series are always so intent on "character development": IT IS NOT OBLIGATORY for the characters lives to evolve in any specific way. Rather, keep all constant, keep the "winning formula" (Winfred Lauder job, group of 4 spending time over beer, Drew/Mimi rivalry, Wick, Steve) and have them do fun and crazy things, but without it having any longterm consequence on the series as a whole. Most series that die off after a certain number of seasons its most often due to this very need for "character evolution". Take Cheers for example. Here's a good example against too much character development. The situation pretty much remains constant for 11 seasons, and its all about small stories that happen to each of them with the pub as a catalyst, and the series itself doesn't suffer as much with time than any other series that choose the other formula. Big Bang Theory was awesome fun in the beginning, with a super horny yet single Howard, a semi-mute Indian character and two brainiacs. Now it just looks like some horrible revival of Friends where they're all in relationships, boys on one side, girls on the other ... etc. Coach is another example of this character evolution leading to disaster. Because as a coach his career must evolve, he ends up coaching some team in Miami, outside of all the world we had gotten accustomed to in Minnesota and the series dies after 2 seasons.