My gaming group instituted a house rule on the Soviet NO. The Soviet Union can get the IPCs for any Neutral territory on the European Mainland ONLY if the Axis powers occupied that territory first. In other words, they would have to take it from Germany or Italy.
We did this because we didn’t like the idea of the Soviets simply walking into someplace like pro-Allied Greece and getting 4 free infantry, 2 IPCs for the territory and the NO on top of it. Also, we didn’t like the idea that the Soviets could attack a strict Neutral, like Turkey or Sweeden, and get an NO bonus for it while turning all other strict Neutrals pro-Axis, which could make things harder on US and UK.