Haven't seen more than a couple games/highlights of Boucher, but I read he's a small kid with meh skating, meh defense, and meh passing. He has a wicked shot and is very smart without the puck. It's hard to base an NHL game on so few attributes, so you work on the meh stuff as he improves in a lesser league.
Matteau was different. Matteau was a good all around player with an NHL frame, so he's learning on the fly. He has the size and talent to be an NHL player at 18. Boucher has other parts of his game to work on before getting there.
The reason I don't think Matteau went back to juniors was because he wasn't going to get much better there. He relied heavily on his size to excel, and he's not going to improve what needs to be improved on there. If he was elgible for Albany, I bet he'd be there. I also wouldn't be surprised if Matteau was sent to Albany when his junior season ends, or even next season.