exactly. i think more people would use the lists if it were a more prominent feature. with G+, they are center stage, so people can easily interface with them.
(I already find myself pretty much just putting everyone in one of two circles now.)
I'm not sure if Google will experience the same thing with Circles. I think what will happen (enter speculative mode) is there will be a large group that LOVES classifying their friends like this, and they will stick with G+. Another large group will HATE it, find it extremely annoying/pointless (possibly because of only using one or two circles, like you mentioned), and maybe stick with FB. Either way, people will most likely end up with an account on both, using one actively and one passively.