The success of RoboCop immediately compelled the studio to make a sequel. Verhoeven wasn't down for it, but they went ahead anyway and hired The Empire Strikes Back director Irvin Kershner to make RoboCop 2, which was a critical disaster. It shouldn't be any mystery why -- the clues are in the plot of the movie itself.
In RoboCop 2, the evil OCP wants to make a whole army of RoboCops, but the new models keep failing because they can't figure out why the original RoboCop worked at all -- an observation so astute that it should have been the tagline for the goddamn movie.
The first film's central arc was all about Murphy the Cop who is also Robo slowly rediscovering his humanity, but the sequel steamrolls all that and has RoboCop's corporate masters reprogram him as an emotionless robot again, because they (and the writers) think that a more family friendly RoboCop is what the citizens (and the audience) want. It's probably no coincidence that this movie came on the heels of RoboCop: The Animated Series.