The idea of back engineering a T 34 was considered by the Germans but ran into a major problem which hasn't been mentioned here that I can see.
The power plant for the T 34 was a V 12 diesel engine made mostly from aluminium. The Germans had no equivalent engine nor the ability to manufacture aluminium engine blocks from scratch.
By the time you've worked out the design problems of getting a Maybach engine to fit, you may as well design a new tank from the ground up utilising the good features found on the T 34.
If the Germans had noted the somewhat rougher finish on the T 34 and moved away from over engineering the Panther to making it easier to produce that might have had some effect on the numbers available to them.
A Swiis watch is a lovely thing to have but if it has a life expectancy of a couple of weeks then twenty Timexes is the way to go.
I believe that some metallic components on aircraft of the time reacted badly with other ones. But if you're only looking to get a few days flying time before it is destroyed or otherwise bent why bother?
A bit of a problem with modern restorations of vintage aircraft.