Well the Panther and Tigers strengths were pretty much negated in the bocage of Normandy while it was multiplied completely on the open steppes and fields of the eastern front. While there were many famous moments told throughout the Normandy campaign with German tanks kicking some serious butt, they were out of there prefferred environment with such close engagement ranges and limited manueverability in the dense terrain. Now a product of the Tiger was its psychological factor known as "Tiger terror" to allied crews and infantry, any tank allied soldiers spotted it was always assumed a Tiger and it took quite a toll on those who had to fight them, it was very demoralizing knowing your equipment was technically worse than the bad guys. HOWEVER they still were superior to allied armor on the western front, so no I do not think they should have stopped producing either, because honestly they were made in different factories and different materials. At the end of the day the result would have been the same no matter what they produced. They both shared there mechanical failings, most serious, hell the Panthers engine blew into flames sometiems on steep inclines and that was happening during Kursk! It wasn't until the Panther G Late that it was becoming trusted by its crews in terms of mechanical prowess (Not firepower or armor). They could not out produce the allied powers at that stage in the war and the result wass inevitable with the allies successfully landing in the west and the Russian steam rolled in the east coming off its amazing victory at Kursk.