Karen's sons (we don't talk about her daughter) are deeply underrated to me, and do have character and stories of their own, particularly in the early seasons and I believe also further down the road. As a newbie I understand that they apparently never quite came into their own as major players despite considerable attempts to beef them up, which is too bad, but I still think they're great. The kids in the various families, with a few exceptions, are actually essential to the show and fleshing out the lead characters - Abby's daughter Olivia has unique and evolving relationships with her, Val and Gary that date back even to story together without her mother in Season 2 when she was very small - and I think that's so important for this kind of show.
And yes, KL and Dallas are night and day to me, as evidenced by my many repetitive critiques of Dallas in this and its own thread since I began watching both.