First of all, do you think Tiago will be part of our squad next season? How much chance does Zanetti have to be injury free with his record? So that leaves us with Momo, D'Agostino(If we buy him), Marchisio, who will surely participate much next season. And none of them is a direct replacement for Momo. Besides, Zanetti wasn't exactly very good when he played this season, what makes you think that with his injuries he will be better next season?
The only negative side of Poulsen is that he has high wages. But to have such caliber player on the bench is incredible. Teams who play 3 days a weak, and who want to win, players on the bench with Paulsen quality is a must.