Looking at my End of Year Season Stats using 15 minute quarters
9 QB's over 4500 yards, Tom Brady leading with 5512 with a Comp % of 61%, 6 QB's averaging over 300 yards or more
31 RB's over 1000 yards with Ezekiel Elliot leading with 1695, 5 RB's averaging over 100 yards or more per game.
50 Wide receivers over 1000 yards with Brandin Crooks leading at 1736 yards and only 3 averaging over 100 yards per game, 8 averaging over 90 per game. There were 25 during the 2016 NFL season
Sack leader Michael Bennett at 20 Sacks.
15 minute quarters and you will get some inflated stats, I believe 12 minutes is the hot spot and has been for many years, whoever I will continue to use 15 minute quarters but will manage the games more closely. Using my sliders CPU vs CPU will get good you better results at 12 minute quarters, but the NFL is based on 15-minute quarters, not 12. I'll take the hit.
If players are trending high and don't get hurt, I would recommend fast simming those games within Madden, when you get to that point probably around week 14, the in-game simmed stats seem more conservative and are not affected by sliders, but you will have enough of my slider stats to be okay at the end, just for the teams and players you need too, in order to keep the End of Year stats more reasonable.
Completion percentages I believe are the best you are going to get with Madden, hence the high number of QB's over 4500 passing yards.
The software has limitations but overall I'm happy with the results
The roster and player ratings used also play a part in this.