The places where they have become nuisances are largely those that have been flooded with multiple competing (usually dockless) systems, because it turns out that you don't need a large capital investment to create a lot of junk sitting idle that gets in people's way.
I think bikeshare systems should be municipally owned (or at least municipally regulated). For me, the real killer app would be one that lets me get a bikeshare in any city.