First, love the game. I play the NHL one too. But there are a few gaping quirks I noticed:

1) Simulations are funky. A playoff game went to OT and the game log said that my opponent started on my 27 yard line. So after gaining 4 yards, they kicked a field goal to win. Another thing I noticed was that one time, my opponent started from the negative-something yard line. So after a gain of 4 yards, it registered as a safety.

Edit: So I seem to get screwed by the sims. My team marched down the field and got to the opponent 15 yard line. On a 3rd and 11 play, the opposing team's running back ran 15 yards to score. None of my players seemed to have any turnovers. Not sure how much the play-by-play things effect results, but some of these things are pretty huge.

2) Kicking is bugged. I've yet to see a player with a kicking rating higher than 50. This leads to awful punts (several that don't even crack the 10-yard mark) and lots of missed field goals. I'm guessing that kick returns are factored, but it's kind of ridiculous how awful kicking is.

3) Player ratings seem to always go down, young players included. Potential seems to be a completely meaningless stat since no player ever comes close to hitting their potential. Young players right out of the draft might gain 20-30 overall over their first 2-3 years, then peak. Other players gain only a few points, or go down. Players seem to gain/lose attributes consistently. I know that players aren't supposed to hit their potential, but it just seems like a pointless stat. I also have spent the 3rd most amount on coaching over the last 3 years. Seems to be the same for all teams. (Edit: Did a test. I had 37 players age 27 or younger, and only 19 of them saw improved ratings, just over half. The rest went down or stayed the same, including the #1 overall pick in the draft. I'm looking across the board for other teams, and it's almost all red. I spend $17.45M/year on coaching, the #3 rate. I'll try bumping it up and seeing if results are improved).

4) Some player stats are weird. The defensive player of the year always seems to go to a cornerback who had exactly zero balls thrown in his direction. I had a corner who was in 1009 total plays and had no balls thrown at him. Doesn't make a lot of sense (his overall rating was only 63, and I had an 82 overall with tons of balls thrown at him). The year prior, the same thing happened, only this time the player had an overall rating of 39.

Maybe I haven't gotten far in enough, but these seem to be consistent. I'm more concerned about #2 and #3, but either way not a huge deal, just wanted to point those out. Thanks!

Edit: Also I think it'd be neat to be able to hire/fire a head coach, each with a coaching style and maybe certain specialties (i.e QB coach or defensive coach). Altering my starting lineup doesn't seem to have much effect on things like difference between running and pass plays.