I can understand all the changes you propose except the reduced earnings for C & Y. When I'm paying that much more to travel in a premium cabin I sure want the points to match it. The earnings in C should not be reduced, Y to 125% could be acceptable. If point earnings have to be reduced, then I'd rather take away the already low EBS 15%.
Priority boarding on international flights only sounds like a good suggestion.
You've done a good job with the proposal. You are however, changing the program pretty much. Is a move towards the american programs really what we want?