[injury log]

That's almost certainly a byproduct of the roster set. If you start a new fictional league, you might start with good coaches or bad- seems random- but there won't be any good ones available to hire. It's definitely possible to outhire the AI teams over time, but this is harder now than in past versions of the game. Still, I'd think that playing with scouts on puts the user at a disadvantage, no matter how good your scouts- you're playing with scouting error, then, and not seeing true ratings. I've never seen any evidence that AI teams actually use scouts- even in Commissioner mode, you'll never see an AI team's scouts on assignment- which makes me think AI teams base their decisions on underlying ratings, not on scouting reports. There may be some scouting error built in there, though, with scouts on- I'm really just speculating here.

Since you'll always be able to hire (eventually) better coaches than AI teams, I keep coaching off to avoid having an additional advantage.

EDIT- of course, if you play, as eriq suggests, with ratings invisible, then what I'm saying about scouting error is irrelevant- and turning ratings off is a lot of fun, if a lot more challenging.