My point is that reverse-engineering aircraft was not the fastest way to get aircraft into service at all. The practical problems caused by not having access to the original blueprints and engineers are quite significant. Aircraft technology was moving very, very fast in WWII. Reverse-engineering a design would generally be a good way to have a second-rate design by the time it actually reached production.
The TU-4 was a bit of an exception because it was dramatically more advanced than anything the Soviets even had on the drawing board (or at least that's what Stalin was convinced of), and because it was such a radically advanced design for the time, it was likely to still be competitive once it got into the air, especially given the drawdown caused by the end of the war.
In the event, it took the Soviets about two years to get their first TU-4s in the air.
If the Soviets had taken, say, a captured HE-111H in mid 1941 and bolt-for-bolt copied it and gotten it into production just in time for, say, the Battle of Kursk, would there have been any advantage to it vs. the Tu-2 already in series production by then?