Ryan Ellis played ~60 games in the AHL before he became a full time NHL'er... I see no reason why Pouliot can't have a similar dev path. Pouliot is already 1/2 way there... ~30 GP in AHL
It's not about number of games played in Pouliot's case. He needs at least the rest of this season + this offseason to mature & develop physically, and work hard off the ice. There's no question that his surgery last year prevented him from doing that.
And he also would benefit mentally just from having another year to mature, lead his team to what is hopefully a solid playoff run, etc.
Bottom line, and anyway you want to slice it, Pouliot is just not ready yet. He got GREAT experience up here, playing some games, getting to practice with the big club, and seeing guys like Letang, Crosby, and others and how they prepare to be great NHLers. Oh, and he got paid nicely while he was up here for that extra week or so, too. This (unforeseen, due to injuries) opportunity was great for him.