Not sure what they're proposing based on the letter. However, I find it interesting that D1 coaches like Mark Berson at USC would support a move of college soccer to the spring in order to assist with player development and such.
I don't think moving HS soccer to the fall would be prudent, but if it was switched I'd imagine a lot of Monday/Wednesday/Saturday game scenarios due to Varsity football on Friday night and JV on Thursday. Not sure where MS football fits in, but if they play on Wed/Thurs, another logistical nightmare. I don't know if the facilities are suited for HS soccer in the fall.
I'd be all for lacrosse moving to the fall or winter however, if needs be. Spring is just too crowded already. I doubt football coaches/ADs would support a move to the fall either due to competition for field space and such (soccer or lacrosse).