A good sable platform to learn is more important at the start than a aircraft with "interesting" handling characteristics, you don’t learn to drive a car in a 1970's Stag so why should you learn to fly in a 1970's aircraft.
I will try and answer your question, at least from my experience with airplanes.
In my first post here I gave my preference for the ideal training airplane picked from the long list of airplanes I have taught on.
The Fleet Canuck was built in 1945/46.
Its handling characteristics are exceptional and in no way difficult to fly because it " IS " a excellent stable platform.
The age of an airplane really is not the governing factor of how it fly's, it is the design of the airplane that counts.
If we go to bigger airplanes my favorite machine for teaching on is the DC3 it is a magnificent design and fly's like a dream and was made in the 1930's.
Modern does not always relate to good.