As stated by many, Dont think Kakashi favours anyone over another.. Kakashi was best suited to train with Sasuke, and he said Ebisu was better to train Naruto than himself.. Now that might have been wrong but I think Ebisu could probably have teached Naruto some good stuff too.. But Jiraya training Naruto is the best thing for Naruto just like Kakashi is the best that can happen for Sasuke.. They both have Sharingan. Kakashi is more experienced with it and can teach Sasuke alot about how to use it and so on, he knows the limits of it's use and all that, Jiraya for instance might know alot about the Sharingan theoreticly but he cant show Sasuke how to use it..
And Sakura isnt in the picture anyway at this moment.. Maby she whould have been trained by Kurenai or Iruka or something if she was in the final fights.