Reeve was also on the crew as a director of the second flying unit and came up with the title's tag: ... Superman IV: The Quest for Peace ....opened to the world on July 24, 1987
I absolutely LOVE all four films equally! It's like having four children I guess. (not counting Supergirl).
Superman IV is my favorite score out of the film series! Followed by III - and then 2 and then one. You find that amazing? Well it's because I know Williams' part one back the front.... inside AND out - and part two isn't so original - it's not Ken Thorne's fault! - While as Part IV "sounds" like one - it's the best of the series in terms of music, and then you have III - which is the most fun score to listen to.
What I recall hearing was the Reeves agreed to appear in the film based on a promise that he would direct the sequel. Superman IV was originally set up with twice the budget, which got cut in half shortly before shooting, resulting in a great many painful compromises. And an unsuccessfully movie, hence no sequel.
I think we can safely count Reeve among those who appreciated Williams' contribution to the success of the first movie. I wish Reeve hadn't insisted on using his own story idea for the 4th one, because, as I understand it, that's why Donner and Mankiewicz were reluctant to come back.