It will make a big difference for competitive clubs in ECNL, MLS Next, GA, etc
The domino effect of players getting shifted around will completely shake up the club teams my kids play with.
Even though my kids won’t have the advantage of being older (Feb/Mar birthdays), I think it makes sense to align the age cutoff more closely with the school year. My 2010 son has 2/3 of his team in 9th grade with the other 1/3 in 8th grade. Our club ECNL season is in the fall so as to not overlap with HS soccer in the spring. So the 1/3 of our team that is in 8th grade doesn’t have anywhere to play during the spring. It also gets screwy for them when my son and the 2/3 of his club graduates HS and the 1/3 have to find another team.