Butyrskaya & Kudryavtsev
Victor certainly gave her the technique. However, Maria always had a lot of psychological problems. She would be perfect at practices, but totally fall apart at major competitions. In fact, Victor ended up suggesting that it might be better for Maria to skate in some shows where her nerves would not be a liability. Somehow, Tchaikovskaya could (temporarily) give the confidence she needed.
Kulik & Kudryavtsev
I understand that Ilya was really not happy with Victor. Victor & Marina have a lot of students, and even though they certainly pay a lot of individual attention to students, they could not make Ilya their "one and only". Tarasova could.
Vasiliev
I fail to see what Totmianina & Marinin gained by going to Vasiliev. They've had their technique from Natalia Pavlova, one of the best Russian pairs coaches. Their choreography has improved, but that is mainly because they are working with Giuseppe Arena (sp?). The rumor went that they wanted to train with Moskvina, but she couldn't take them because of Berezhnaya & Sikharulidze; she suggested they temporarily train with her pupil Vasiliev. They feel the partnership is working, though I've heard rumors they are heading back to St. Petersburg.
Morozov
I know he coaches as well as choreographs. However, while I think he has proven himself as the latter, we have no way of telling how good he is going to be as a coach.
Coaches who work with beginners vs. "final polish" coaches
Jaana, I am not sure I agree with you. Russia has two excelent pairs coaches who seem unable to give that "final polish" -- the Velikovs and Natalia Pavlova. Velikovs' pairs include Shishkova & Naumov and Petrova & Tikhonov; Pavlova's include Eltsova & Bushkov, and Totmianina & Marinin before they went to Vasiliev. Interestingly, out of the Berezhnaya & Sikharulidze, she used to be coched by Pavlova, and he by the Velikovs. Anyway, I feel that Petrova & Tikhonov could have been really great with another coach.