I don't know if docks are an essential part of the formula - I'm a bit worried about how inherently monopolistic the dock model is - but the dockless model seems like it is inherently in conflict with the idea of keeping the public right-of-way clear for public use. Real estate around places like train stations and major destinations is scarce, and companies really shouldn't have unlimited ability to use that space for storing their equipment, free of charge.
I suppose the city or private property owners could reserve the right to collect nuisance bikes and hold them for bond, sort of like towing improperly parked cars. If bike sharing companies hold the person who got the bike "towed" responsible for any fees resulting from where they left the bike, similar to what would happen with a car share program, then maybe that would do the trick.