Stalin's starvation genocide in Ukraine estimated at 7.3m dead is a historical fact. However, what is lesser known that the victims were mostly located in breadbasket region of Central and Eastern Ukraine, that means the majority of the victims were ethnic Russians, not ethnic Ukrainians.
This is not to say that ethnic Ukrainians did not die in Holodomor. They did, but they did not constitute 7.3m.
Nationalist ethnic Ukraininans played this card for too long. Sooner or later it will backfire on them.
Western Ukraine is more agricultural than the East, which is (and was then) much more industrialized.
Here's a graphic purporting to show population loss by region of Ukraine. It doesn't exactly support your claim.
http://cybercossack.com/?p=3304