Any ban connected with the severity of the injury is inherently problematic because it would need to be based on the prognosis of the player. A player with an ACL injury might be out for 9 months or 15 months. It depends on their rehabilitation and loads of other stuff. It’s impossible to base a ban on something so uncertain.
If we’re going down that route, dangerous tackles need to be reviewed post-game by a panel and hand out bans based on the dangerousness of the tackle and taking into account the seriousness of the injury.
I’d be absolutely all for players getting 10 game bans. Would stamp out the sly and vindictiveness fouls that happen from time to time.