Despite ShB having a brilliant story, there was still a lot of filler. Every time you're on your way to the next confrontation you have several hours worth of menial labor to do ahead of time, whether it's repairing a trolley, a lift, or whatever. I can't think of any single player RPG I've played that essentially has 'speed bumps' to keep you from tearing through the story too quickly. Just because the MSQ is a soloable experience for the most part doesn't make it play like a single player RPG, it's still an MMO that has to drag out a certain amount of play time.