Yeah, I definitely agree with the sentiment in this thread. It was perhaps a little worse a couple years ago, when it seemed like every other episode involve some sort of raid by a bunch of suit-wearing guys and the kids were merely along for the ride.
I too am wondering where characters like Jimbo, Ned, Mayor McDaniels, Barbrady, Bebe, Clyde, Timmy, Dougie, and Big Gay Al have gone off to. The parents--minus Randy, Lianne, and a couple recent exceptions like Sheila--have been used less and less too. Sergeant Harrison Yates has all but replaced Barbrady entirely, and while he's not a bad character, I'd like to see the two of them actually interact for once.
So yeah, the stories seem more current event driven than character driven, and they wedge the characters in there to make it South Park, but they often don't do much central to their personalities.
That said, I love South Park's take on Canadians, with their bizarre flapping heads and quirky voices, so I'm still looking forward to this one.