Ukrainian Catholic Primate Crucial to Relations with Russian Orthodox Church?

Roman Catholics believe that the next primate of the Ukrainian Catholic Church will be crucial in determining whether Pope Benedict XVI of Rome and Patriarch Kirill (Gundyayev) of Moscow meet in the near future. Some Russian Orthodox would counter that the very existence of a primate of the Ukrainian Catholic Church (not to mention of the Ukrainian Catholic Church itself) is an obstacle to the two meeting. For the former perspective see here.