Quite a detailed analysis by Hamar, I can agree pretty much.
It also depends on the ruleset, as has been stated before. I often play with Soviet Sovereignty (also known as Stalinist Xenophobia or Paranoia) where UK/US troops or forces may not enter Soviet held territory as long as the SU is alive. In that case Finnland/Norway is not important for funneling Western troops to the Soviets, while the West can support the Soviets less in other ways than letting them have F/N.
Even without this rule, in most cases Russia can get as well as use it best. So my vote would be for Russia.