How would Shirou and Fate/stay night's story overall be different if Kiritsugu properly taught him magic and told him everything?

How different would Shirou and Fate/stay night's story have been?

By "everything", I mean things like the holy grail war, the other mage families living in Fuyuki like the Tohsakas and Matous, Kiritsugu's own history, and Ilya and the Einzberns. Also, what if Kiritsugu actually nurtured Shirou as a mage? How differently would the routes have gone? Do you think they would even happen in a similar way?