Just an idea, maybe its been talked about before, not sure.
But what if at the beginning of every season, you get the option to pick an assistant coach. The coach would have a specialization or point of emphasis. So if my team needed to improve shooting, I would hire a 3pt specialist, and my players perimeter ratings would improve slightly faster than normal that year.
I know this general idea is on the show, and madden i think, or maybe nba, idk, I'm not saying I came up with the idea, i just think it would be cool to add. At d3 and d2 maybe the coaches aren't as good so they come with a positive and a negative.
Another idea, instead of assistants, the head coach could earn perks throughout time. Kinda like the skill trees in NCAA Football 14. As you achieve things as a coach you get small perks along the way. This would give coaches something to work towards long term, but could backfire by creating an uphill battle for new players.