Significant numbers of the Pershing (equaivalent to the German Panther) could have been put into production earlier. If that would have happend a lot of Amreican lives could have been saved. Expending 2 or 3 Shermans to take out one Panther would not have been the tactic of choice with the Pershing. Some historians blame Patton for interfering with speeding up Pershing production.
“Expending 2 or 3 Shermans to take out one Panther”
Actually this was not the US Army tank doctrine. The idea was that the Sherman would support infantry and as soon the German big cats showed up they would radio in the tank destroyers like the M10 and M18. So not sure Patton can be blamed for all of this.