Lacrosse and Softball both adopted these rules a few years ago, so we don't really have to guess what the impact will be. Top talent will still be identified and evaluated early (grades 8-10), there just won't be recruiting contact with those kids. Recruiting coordinators will still get to know these kids through watching them play and by talking to their coaches.
But you won't have as many young kids stressing over deadlines for choosing a college. You won't have weekly check-in calls by 9th and 10th graders. You won't have U15 coaches arranging calls between players and coaches. And you won't have 9th grade commits getting cut lose 2 or 3 years later.
It's no panacea, but I think it's better than the current system.