Without wanting to start the debate again, I have come across some material from 1977 when City first adopted an all-Blue kit while researching for the next "Big Book Of City." Anyway, there were letters complaining about 'City's awful all-blue strip' (written by someone called B Pullan from Heywood). Pullan asks why the club has ditched white shorts - 'that strip was presentable, smart, neat - and famous.'
The official response came back explaining why City changed to an all-blue: "The reason for the change was the problem encountered with frequent colour clashes resulting in City having to change from white shorts. Our alternate colour was then black shorts and that did not combine at all with blue."
So that was the reason then. Nothing to do with look, style etc. Simply to avoid clashing. Things were different in 77 when the Club tried to wear home colours at away games as well and only change when they absolutely had to, but personally I don't think it holds up that well as an excuse. We could have worn blue & white at home and our away kit on our travels if there was a clash.
Nowadays, short clashes are not viewed in the same way and clubs can even get away with wearing blue shirts when facing City (Everton for example).
Anyway, thought I'd share the reason. Incidentally, the idea of an all blue kit lasted until 1985 when Billy McNeill insisted that they ditched blue shorts because he thought blue and white was well-known as City's kit.