BTW the batting average in play on those 0-5 degree grounders in MLB is not bad (around .400) but the Overall production is much lower because you don't get extra base hits except the rare down the line ground ball double. for example for 0-4 degrees the BA was 419 and SLG just 465, meaning the ISO was just 0.05 (MLB average is around 0.15). with a 5-9 degree angle BA was .570 but again ISO only .076. the first time ISO gets above league average is 10-14 degrees (.19). it is very hard to be an average or better hitter with a below average ISO because that not only lowers your SLG but often also means you don't walk at higher Levels even if you are Patient because pitchers will not be afraid to attack you because the worst that can happen is a single. to be above average with the bat with a below average ISO you basically have to contend for batting titles (see Ichiro).
above 14 degrees BA starts to go down but ISO goes up. for example at 15-19 degrees BA is down to .619 but ISO is up to .343. Slugging at both angles is about similar (around 960).
That means above 15 degrees is probably were no power guys start to lose. maybe low power guys with Speed should aim for 10-15 degrees instead of 15-20 but that still means that the back of the Cage is still the very lower end of the Launch angle range for those guys.
Data is statcast data from 2015
http://diamondkinetics.com/hig...g-vs-home-run-swing/
