For the average user, I would disagree. If I had the choice to easily swap out the MUI for start when I first installed 8, I would have done it in a flash. Over a year later, I am hoping they won't force me to use their ancient start menu from the 90s. Sometimes you have to force people to try something new to get them to really see its benefits.
In the enterprise context, however, I agree that the start menu would have assuaged any doubts businesses had about whether they would need to retrain their employees (maybe an enterprise version with the start menu would have served the purpose of pushing the public to try something new while leaving a safe option for businesses?). Even though that type of user just puts everything (eeeeverything) on their desktop anyway. The start menu does open up the avenue for enterprise adoption, but I hope it isn't mandatory for home users.