The advantage I'm talking about isn't the advantage of the injuries, you can't make up for a Goff or Gurley injury, that's just a disadvantage we have to accept (praying this never happens, knock on wood). Without a key player, we may not be as good.
The advantage I'm discussing is more mariginal, but since the game of football is a game of feet and inches, those margins still matter. The advantage I'm referring to has to do with
subbing players in and out during the course of the game. A team with 53 players active on gameday could rotate players, subbing players in and out during the course of the game to keep their players fresher. And I agree with
@dieterbrock, this improves the game, but that effect only applies to a team with no injuries. If the other team(let's say the Rams) is getting riddled with injuries and can only field 46 players, they not able to stay fresh, not seeing that increase in the quality of the game we all want, and clearly at a disadvantage before the coin is ever flipped!
Putting it in the context of a different context, if you are in a fight, do you think its easier to:
1. Fight 1 person 1v1 OR
2. Fight that same person 1v1, except he has a backup that can sub in for him when needed?
Option 2 is harder, regardless of any other factors. And that is what 46 v 53 is. And that option is mitigated by forcing an equal number of players competing on either team by designating some players as gameday inactives. We can still discuss expanding the size of the roster, I'm on board with that idea, but I don't think it's a good idea to get rid of the game day inactives. That would unnecessarily tip the scale in one teams direction. Any given Sunday would turn into Any injured Sunday.