As far as there not being enough time, I think that Vito looked upon Michael's involvement in politics as a way to enhance his nefarious undertakings. I don't think legitimacy was in either Michael's or Vito's mind.
The "not being enough time" line could be construed as meaning that there was not enough time to set Michael on a legitimate path or that there just wasn't enough time to get Michael ready for the position in the family that he was about to take. Personally I've always thought that it meant a little bit of both.
However, overall, they both desired a world of legitimacy. Vito knew that it was not possible for himself to be legitimate. But you can rest assured that Vito wanted it for Michael, and that Michael wanted it for Michael. Vito even tells Michael
But I never -- I never wanted this for you...... but I thought that -- that when it was your time -- that -- that you would be the one to hold the strings. Senator -Corleone. Governor - Corleone, or something... It can't be made any clearer than that.
As for Michael, the whole premise of GFII and GFIII is his desire for legitimacy! How many times have we discussed how Michael tried to make things different in GFII with the move to Nevada, surrounding himself with the upper echelon of his new world. How he began to make political contacts out west. While they may have been a facade in a sense, they were also Michael's way to fool others and even himself, into believing that he was, or at least on the path, to becoming legitimate.
And what takes place in the evolution of Michael's character in GFIII is just further proof of his desire for legitimacy!
