Everything in the game is a L2P issue in some way.
Obviously kubel can be countered by way superior tactics or micro.
But isn't that the definition of overpowered.
"Can only be beaten by way superior skill or tactics".
In 1v1 2 kubel opening is deadly on some maps and almost impossible to beat as USF or soviet T2. It also is mindblowingly easy to pull off, no skill needed.
In team games it is way worse.
And I really do not see how a fuel cost can change anything or a manpower cost.
As it does not change anything, if you are stuck in your base
When lots of people are using cheesy tactics in everyday games.
Like 2/3 of all games vs OKW the Kubel + 1 Sturmpio rushes enemy cutoff or base.
Thats when problems get obvious.