There is significantly more to it than that, Walt.
Hitler desired the slavic regions, but he also desired other things. He sought the unification of Germanic peoples for example and sought this by expansion. He also desired, and sought with his ally Mussolini, a mediterranian conquest. The expansion possibilities beyond that were likely and are anyone's guess.
Evidence of the expansionism comes from a major plank of German national socialism's beliefs. Hitler and the Nazis believed themselves and Germany to be the embodiment of superiority in the world - in science, in technology, in ethnicity, in practically everything. The concept came out of the philosophical writings of German marxists during world war I. The nazis saw as almost a destiny the emergence and dominence of "Mitteleuropa" - the middle-lands of Europe, or the German states. They wrote on end about how the "Haendler," or merchants, were in a societal competition/clash with the "Helden," the heroes. Germany was to them, of course, the state of heroes in the world that was destined to win and owed the leadership of the world. It was a truly bizarre train of thought and one firmly rooted in marxist philosophy with a strong hegelian influence.
Well, that is just false.
Hitler saw the Brits as aryan, but he sought a peace with them, not unification. You can look at German policies in every occupied country. If extermination is unification, you may have a point. Hitler didn't seek to "unify" with the Czechs, or Poles or anybody. He sought to use them like beasts.
Walt