Like forced barbed wire, annyoing thing acutally. And they can build bunkers, trenches and AA 2cm with Defensive doctrine - would like to have that doctrine for USSR for to teach their engineers to dig MG bunkers. (And yea, I know that 2cm AA suck, don't remind me.)
And of course, they only repair faster, not build. But still, in late game speed of repair of your tanks can be veery important. Its very funny to see, how my 2 soviet engineers working hard and long for to repair my IS-2 or ISU, when OKW's pioneers repairs KT or JT like they are modern engineers from MIT.
And they perform not like "1.5 eng", but like 3-4 eng. Don't forget, that they fight 3-4 times better, than any other engineers without upgrades.
3-4 Soviet Engineers would beat 1 sturmpioneer. Infact a conscript can beat a sturmpioneer. If you are losing to sturms, you're just not approaching the situations appropriately. You don't charge sturms sitting in cover, that's recipe for failure. You don't charge anyone in cover unless you have the ability or numbers to take them on (ie grenades or superior numbers, flamers). Not only that but you've stated over and over the different abilities of the two factions. You never quite seem to put any weight behind the fact that soviets get flames non-doctrinally and OKW has to be a terrible doctrine to get access to a single flamethrower. Do you have any idea the nightmare OKW faces when it's nothing but Maxim spams in buildings and all you can do is stare at them? You can't toss an incendiary grenade when you're pinned to the floor by instantly turning maxims.
You're looking at the Sturm in a vacuum, without considering what supports these units. The pop cost shouldn't be overlooked either. I'd much rather have 2 Soviet Engineers walking around, planting mines, making barbwire than having my sturm, I also get to flame shit out of buildings. A unit which needs to contribute to fighting as much as possible to keep up with the enemy.. so you fall behind mining while soviets can just spam mines without any real munition dump. You don't need to pay 90 for a single shreck, or 60 for a mg42 on your Obers, or G43s, etc.
You forget how many nerfs OKW has undergone already, sturms have been nerffed, veterancy has been nerffed, obers were nerfed, then nerffed again after losing their guns despite costing 400 manpower, requiring Tier 4 and costing 40 to reinforce. The rakten dies to any ambient shot, as it doesn't benefit from the green cover bonus that all over AT guns benefit from (including the ZiS). Sturms need a fast repair package because often you only see 1 or 2 OKW tanks in a serious game and you have to be able to repair that precious 200 fuel Panther when it goes into battle against 70-80 fuel Su76's that have the same penetration as an su85.
When balancing a unit, you have to look as the faction as a whole, and making a 9 population sturmpioneer squad that has to pick between combat and being a regular engineer is not a bargain any OKW player wants. Not unless that assault squad becomes 6 man with some armor. Then I'd agree, because everyones been screaming for mp40 upgrades on Volks so we can get rid of the shreck blobs that allies AND axis hate because it makes OKW infantyr play a bit bland without taking doctrinal units.
I'll support the Sturm change as long as the sturms become definitively better. Instead of just becoming an overpriced repair monkey.