I was at the ASA National Convention last October when this was voted on. There is strong feelings on both sides. Until the high school pass it, I don't expect ASA will. The big problem is that 16 & 18U play high school ball... will there be support to change both to 43' if high school pass it??
Personally, I think that 43 is just a number.... just a higher one than 40. I do not think it is a big deal for pitchers to adjust. The ones that can't get it over the plate at 40 feet, won't get it over at 43. The average h.s. pitchers throw as many high pitches as low ones... it's not about distance, it's about accuracy.