I actually think the majority of this season has been lazy and more sitcommy/dumbed down.
If you go back and watch season 1-9, it's just not as cleverly written, the improv isn't as smooth, the editing is off and obviously the actors are much older and don't seem to have the same energy.
Obviously it's lacking some key players (Funkhouser and RL, even though the latter was part of this last season, you feel he was used sparingly as he was in such poor health)
Vincent Vaughan is an odd choice as a replacement Funkhouser. For me, he's too big of a name to be playing a character, and not himself.
It's still watchable, sure, but like many shows, it's definitely gone on probably longer than it shoukd have done.
I did feel like when LD split up with Cheryl the show started to go downhill slightly (although the season in New York and the spite store season still had huge moments of quality). Every other season since that point has been average IMO but others may disagree.