To say that a full stack developer is not innovative is kind of subjective. Even though it might be the case that more people can have more input, it doesn't mean that the full stack developer does not have any input at all. On the contrary a full stack developer would have a better understanding of the big picture and come up with the big idea. It might take longer for the full stack developer to come with the idea, but it's worth the wait. That's just my humble opinion.