I think it's a fair point to make that it is quite common for 19 year old players to struggle in the AHL, but at the same point, what benefit is there for someone like Poulin to play in the Q next year? He's already physically dominant over the average player in that league, and it's only going to be worse next year. It's not fair to the Q teams to have all 19 year old CHL players be able to play in the AHL, because a vast majority of them are going to struggle in the AHL, but it's also unfair to the players to make them go play in a league that they're clearly above just because they're not NHL ready.
I don't think the 1-2 exceptions would be a good rule, either. What if you have more than 1-2 guys that should be playing above the Q? What kind of message would it send to say Legare if Poulin got to play in the AHL (and earn a lot more money) while he has to stay in the Q? If I could make the rule, I'd make it that any 19 year old junior eligible player who starts his ELC by staying beyond 9 games in the NHL can be assigned to the AHL. It doesn't make sense to me that a team has to use years on a player's ELC while not being able to keep him in their farm system. Guys like Sprong in 2016-2017 shouldn't have to go back to the Q at age 19 when they're in year 2 of their ELC.
I don't know that just saying "if you put a 19 year old in the AHL, you have to use a year on his ELC" will prevent teams from abusing it. Telling teams they have to give these guys a standard 9 game trial in the NHL may prevent it. That would make it so that only players who are clearly out-classing their respective junior leagues will be AHL eligible. I'd honestly even be inclined to expand this to not even include an age range, where if you're starting your ELC, you should be able to go to the AHL.