The idea for every nerf or removal there needs to be a buff is insane and stupid and has no bearing on Relic's history at all. We have seen a constant nerf to OKW's early game since WFA release and see no buffs or changes at all to help it.
The issue with Demo Charges is that they punish smart players AND stupid players. 1 demo to instant gib a single squad with Vet and an upgrade is excellent. 1 dead Vet 2-3 gren with a LMG42 is an excellent trade for 90 munitions.
So yes, it does punish blobbers, but it also punishes people who makes use of spreading out squads around to map to cap and cut off people because 1. You can't spam Sturms OR Pio's, and 2. You can't spam the upgrade either.
Mine detection for Axis is neither cheap nor plentiful, making demo charges a very large issue even in higher skill modes.
The increasing of OKW's munition income, and Kubel buff would disagree with your first statement.
1 vetted gren squad with an lmg is a perfectly good trade, its a fine use of a Demo. I watch a lot of high level play and demos do not supremely punish any of them. They might take a loss here and there but they are never utterly devastated like lower tier players whom loose a lot to demos.
spreading out has its pros and cons, you have a higher chance of detecting a demo or mine and yet you also have a higher chance of missing a demo or mine depending one how far you are spread out.