I don't know about sitcoms, but since my kids are pretty young, I've seen a lot of children's TV in the last few years. There's a lot more shows that center around black kids, and a lot more shows with black kids as smart or hard working or wise that I remember from the past. It's not so much built on stereotypes. If I had one complaint, it would be that black boys don't seem to be portrayed to the same extent as black girls and black fathers aren't as present as black mothers in a lot of the shows. That might not be true across the board, but it is the impression I came away with from the shows my girls watched. That's not to say black males aren't portrayed well too. It's just that all the shows seemed to have the black girls as strong leaders, smart, or demonstrating some other good quality. While it was a mixed bag for the boys.
Yeah my oldest, 9, got a bunch of shows he watches that have little Black kids in them doing all sorts of shit. Got my dvr full of them episodes recorded.