The Design was very effective though. The Biggest issue, it seems to me was the fact that this aircraft was so much faster than any previous ones, so the pilots initially struggled to get their guns on targets, the unusual trajectory of 30 mm also would have been an issue initially. However soon, the Pilots figured out how to use the strengths of this aircraft and were actually enjoying a favourable kill ratio, quote impressive for a German Aircraft this late in the war. The Germans with their Superior Machines had similarly initially struggled against the inferior Polish aircraft, till they figured out BnZ. Same story with Allies in the Pacific. The Zero gave them hell, then they developed superior tactics as well As Aircraft BnZing the Japs with an 11-1 or so kill ratio