I am forgiving of this defect for the reason that my attempts at aircraft in Kerbal Space Program have mostly had the same issues! There is a very, very small difference in design between an unstable plane and one with practically no pitch control at all, and the ideal configuration is found just between the two.

My understanding is that this was intentional. They thought instability was needed for their desired maneuverability. Today we see this as the wrong answer to the question of whether an airplane should be stable or unstable, but it shows how far ahead they were that nobody else even knew enough to ask that question.

This is true again for the most advanced fighter aircraft, except the active hand is now a computer.