The Bergvall incident at the start of the game shows how important it is that concussion substitutions come into the game. Take him off, do an assessment, if he passes it then he can come back on. Having permanent substitutions will make it very tough to get players to go off, especially if it turns out they’re just dazed and not concussed.
Agree 100% in principle, but I need to be shown how it can be successfully deployed WITHOUT teams using it to their advantage. For clarity, I mean faking a head injury to give a player a break (or have an "impact" sub for 10 minutes) and then return him to the game.
In rugby union you have an independent match doctor that oversees these things and I can’t remember any controversial incidents. Regardless head injuries are more important than any of it anyway when we consider the amount of early onset dementia related deaths there’s been in the sport.