It's hard to tell if Alfredsson's declining. The Sens were physically not allowed to play offence under Hartsburg. The season before, Alfredsson was leading the league in points at the All-Star break before getting injured.
Injuries are a concern with Alfredsson, but he seems to be a miraculously fast healer. Or, more accurately, he refuses to let injuries prevent him from helping his team. You'll see him come back after surgeries or broken jaws and only have missed 1 game.
Savard is a great player, and I think he's becoming more well-rounded, but I think he's still far more one-dimensional than Alfredsson. Alfie is still better defensively, brings more of a physical element to the table, and is undeniably the leader of his team (although they weren't half as good as the Bruins were this season).
I think Alfredsson is a superior player today, but I'm going to have to echo the sentiment that if this is for the future, Savard is my pick (although Alfredsson's game is so smart that it shouldn't decline that much over the next few seasons).