Voice of Reason:
I'll answer those points for you. The High School League should address the first 2 in that they need a mercy rule. If there is a 5 goal differential by half-time, game over. If it reaches 5 in the second half, game over. They should do that now regardless of changing the laws re: subs. Don't forget, you can still use 3 subs.
As for "younger talented players" they will always get a chance, and if they are that talented, they can get a starting job for themselves. It should motivate them to improve both in practice and when they do get on the field, instead of sulking on the sidelines like a lot of them seem to do.
Someone also mentioned refs keeping track, limiting subs to 3 per team all game is easy. All score cards that the refs use have 3 lines at the bottom for subs. Just record them as they happen, that's easy.