I live a stone's throw away from Blackwell & fish it a ton since its next door - it is definitely a high traffic lake, but not nearly as much with boats. I take my kayak out and have caught 80+ crappie in one morning/afternoon, 10+ bass in a day, but then I'll get skunked some days. That's fishing. Some decent northern in there as well. One of which was about 36", but looked sick considering it was slowly swimming at the top of the water. They'll chase spinners/mepps/roosters/swimbaits near the shores. Giant carp in the lake as well.
In terms of the weeds, no question that parts get pretty stinkin weedy. Especially the channel connecting the two different parts of the lake. Weedless soft plastics and a braided line were my solution and have no problem with it.
Great place to try out new techniques, catch a few fish, and the forest preserve police are good people out there.
Hope that helped!