I'm wondering if this might actually help the German war effort following Barbarossa, assuming it still happens.
This sounds like an interesting scenario. Any idea or speculation on how it would develop through the 1930s?
Both these questions are somewhat related so I hope you don't mind that I combined them.
Porsche is going to have a negative effect, just as he did on German war production. The size of that effect is going to depend on how much power Porsche actually wields and the length of time he wields it. The more of each the more negative the effect.
There's another T-34 thread currently active on the board, so let's use that as an example.
We all know that the T-34 prototype lost out to another prototype during trials but a chance decision by Stalin saved the T-34 program from being terminated. Assuming Porsche is made the USSR's chief industrial commissar and assuming Stalin backs Porsche's various decisions with the full force of Beria's wet work boys, what would the chances be of the T-34 program being saved on what was basically a whim?
Now, spin that same question out across the entirety of a nation's industrial production. Beginning the see the possibilities?
The USSR produced a lot of junk because the USSR's centralized command system allowed politically connected projects to continue well beyond the point where their limited worth would have led to their being shut down. We must remember however, that this same politically-focused centralized command system saved "losing" programs, like the T-34, which eventually proved wildly successful.
The USSR's politicized command industrial system also didn't fit well with things like quality control and the relative lack of quality control is another reason why the USSR produced a lot of junk for decades. Would Porsche be able to impose an apolitical application of quality control? Again, that would depend on how strongly he's backed by Stalin and for how long, but I'm not betting on Porsche making either profound or long lasting changes in this area.
In Porsche's hands, I see the USSR moving towards more of a "perfect" design approach for it's many needs than the "shotgun" approach it's heavily politicized system employed. There would be one "perfect" light tank, one "perfect" medium tank, one "perfect" heavy, one fighter, one bomber, one of this, one of that, etc., etc. and that mindset would fit neatly with the the theory, if not the practice, of the USSR's centrally commanded economy.
This narrowing of choices is going to greatly lessen the number of equipment options the USSR has once war breaks out and greatly increase the chances that one of the "perfect" designs is in all actuality a perfect disaster.
Porsche isn't going to last long the post, I can't see him lasting more than five years for various reasons. The sooner he leaves, the sooner the USSR's industrial system metastasizes under political pressure into the "shotgun" set-up it "enjoyed" in the OTL.
However, while he's in power, or whatever power Stalin truly allows him, Porsche the Toymaker is going to make fundamental decisions based more on what's "kewl" than anything else and those decisions cannot help but negatively effect the USSR.