Panzerfusiliers with a reinforcement halftrack would be a recipe for disaster.
That's debeatable considering that by the time they get their g43 light vehicles are rolling in. But anyway it could be a 250/1 with open top
IR STG44 Obers are great at assaulting, they fit the doctrine theme just fine.
That's also debeatable, assaulting? Mg34 Obers are better in most cases even when you factor in the cover bonuses
https://youtu.be/n3sOwWL6-vI
Obers abilities don't fit such upgrade either, it doesn't have offensive smoke, it could have used having Panzergrenadiers Breakthrough equipment smoke grenades
It's a great upgrade even though it's limited to only one unit. It's there to balance out the raw power of the other abilities.
IR Obersoldaten have no business in a doctrine that has Panzerfusiliers, it's that simple. Nobody is going to use Obersoldaten when your mainline infantry you crippled your early and early mid game with is starting to shine and can finally reward your efforts.
Can you point me any single game in a tournament, even teamgames where OKW Grand Offensive was chosen and Obersoldaten ir hit the field?
Yeah, you could argue that having a 280 mp unit perform as a 240 mp unit for half game and then as a 300 mp unit for the rest is not supposed to happen, but unfortunately this happens. Panzerfusiliers in late game are just too good for Obers to be an option, even more for a situational upgrade like ir stg.