The addition of the IFI control system was huge, BUT

I think the sharing of drivetrain designs. The level of competition has gone up through the roof since people started doing that. By seeing these designs, people have been inspired to take them, modify them to ways they feel are better and go publish them to share...wash, rinse, repeat...etc

People are inspired (that I word again) and the level of competition goes up...it's a win win situation for everyone