Personally, I thought SS had the perfect amount of content to offer. Assuming you did everything it had to offer and not just blow through the story mode. I racked up quite a few hours upon completion of this game in the end.
How do you do anything
but the story? That was basically all SS had to offer, apart from the usual heart pieces. The sidequests were relatively uneventful, and it would be unfair to other games to include them in your judgement of length.
For all the cramming Nintendo tried to do with SS, I think the game would have been better on a larger scope. It took my just under 50 hours to finish the story, which is more than what its predecessors have usually taken me. Yet I feel like I did a whole lot of nothing. To be honest, I didn't think the story was all that it was hyped up to be. I know the gameplay of SS wasn't built on the story, but from information from Nintento it sounds like they put a little effort into making the story something special. I also know that a lot of people liked the story elements that SS brought to Zelda, such as Zelda's sealing through the Gate of Time. I wasn't that touched by it, but I respect it, and what others felt. But for a game that touted its story more than the games it followed, not a lot was happening. Look at Ocarina of Time, Majora's mask, the Wind Waker and to some extent even Twilight princess. There was always some drive in story every step of the way. The lack of drive and the closed in areas are what made SS, for me, feel particularly short. I had no problems at the time that I was playing, but a few months after finishing the game I struggle to remember anything but the bare basics of the story.