G. Michael Maddock and Raphael Louis Viton make a really important point about engaging teams in innovation projects in their current column on Business Week's website. Here is an excerpt:
Team building works differently from idea building. Once you have an idea you like, don’t ask a committee to agree that it’s a good idea. If they have not been involved from the beginning, it is too late to involve them now. If you bring them in at this point, everyone will chime in with small changes. The result? The idea dies the death of 1,000 cuts. You now have a dumbed-down idea without the head-jerk impact that the best ideas need.
I agree completely, though I would add a second reason for why this strategy often fails. In some cases, you will experience death by a thousand cuts. In other situations, the team will feel as though you have simply presented plans as fait accompli. They may become very disenchanted as a result, and they may not commit fully to the implementation of that course of action.