Successful junior clubs over the long term ( 8-12 years) are those that recognise that good coaches are harder to find than good players, and that good age / team co-coordinators are FAR harder to find than bad parents.
Good coaches develop good players, have these coaches at the u10 and u12 level and you have it made. Because then your u14 players actually attract better coaches and the cycle perpetuates.
As soon as you let a parent coach their own child , or allow coaches to follow "their" players up an age group, you are now on the downward slope.
good coaches do not want to do administrative stuff - recruit good managers who will do that for them - and you can attract and keep the coaches.
Virulently Protect both from the over enthusiastic parent .(NB if every few seasons the club kicks a "good" player out because of their parents, you will then find the other parents pull their head in - losing one player and a pair of disruptive parents is actually GREAT for the rest of the club)
Melbourne tigers had a great junior program for years, their head u12 coach for years was one of the most experienced senior coaches in the state - Ken Watson.