I understand why W Russia/ Belorussia makes sense.
To me the issue is one of choices and options, rather than IPC values etc. A successful attack against the Ukraine limits Germany’s opening choices. They have to kill the Russian armor in the Ukraine, so that’s one place they have to go. Only 5 German Fighters means that difficult choices need to be made regarding their usage.
For example- we’ve all seen the Sub/ 3 Ftr opening against the British Battleship result in both a Sub and Fighter being lost- a 4th Ftr usually means you only lose the Sub. Killing the Battleship in one round also means a 33% chance that you keep the sub. Nice to have that sub as Germany.
In Egypt- personally when I have 6 German Fighters one of them goes along with the Bomber to make sure the battle only lasts one round- otherwise the Brit Fighter will probably get to swing twice. The difference between having 1 Armor and 2 Armor in Egypt for Germany is huge. If you kill them in one turn you might even end up with an Inf left as well (50/50 chance in a 1 turn battle), which completely stops Britain from taking back Egypt on UK1, almost single-handedly ensuring that your economy ends up around 45-47 until the inevitable Allied cleansing of Africa.
Finally, if Germany has to go to the Ukraine, the northern thrust is weakened. IMO Germany going heavy in the north is much more deadly to Russia. The typical lone Russian in Belorussia is an easy kill, whereas 2-3 Russian Armor in the Ukraine needs around 3-4 Inf and one of your Fighters to get the job done.
A German Artillery and Armor are also nice to kill.
Yes a Ukraine attack weakens Russia’s offensive capabilities, but it does the same to Germany.
My final caveat is that I play the Axis with no bid. It’s a good challenge and a victory is more meaningful to me. The ability to add a German Infantry to either Libya or the Ukraine, along with a couple of extra IPCs to spend might change my thinking. As is I still think W Russia/ Belo is a smart opening- I just like the idea of crippling Germany in a more significant way right out of the gate.