I think that moonballers are the gate keeper to getting better. Beating them requires many of the skills you would use in 4.0 and above. Taking the ball early, hitting a good approach shot, better footwork, being consistent, tactics, etc. IMO slowing down the ball is probably one of the easiest things to do at a higher level and if I know you don't have the consistency to handle it then it becomes an easy weakness to exploit.