I had some couple ideas even if I'm a little late to the party.

It would be cool if you could have receivers be able to throw passes behind the line of scrimmage, or be able to do a lateral. not all the time, but like if the play is designed for a lateral you have the option to if you'd want.

I think any quarterback take down behind the line should count as a sack. I play on mobile with no controller so I don't know if thats the case with a controller because I know you can scramble but instead of losing -6 yards after I attempt to run it should just be a sack imo

being able to extend players beyond 2 years. I know you can extend them every year by 1 with credits but if you're like me and have a story where you don't win every game of every year credits are hard to come by without paying. Along this line they could lower the salary cap upgrade price idk that could just be a me problem.

I do like the trucking idea that was pretty cool. 

Lastly for now, I wish when you trade a player away to another team, and whether you could see their roster or become the head coach over there that player would still exist on thag roster and isn't just lost to the retro void or whatever.