A best practice at Fortune 100 companies is to see the front end of the pipeline not as fuzzy, but as crystal clear.  A systematic approach to innovation using an effective process can take away the mystery of the front end and create a sustainable growth engine. 
What is the “fuzzy front end” and why has this notion become so popular?  Calling the front end “fuzzy” perpetuates the myths of innovation.  “Fuzziness” is the term coined to suggest that innovation has lots of risk, is not systematic, and is more of a “eureka” moment.  One can schedule work, but you cannot schedule invention.
This is simply not true. You can schedule innovation.  A company like GE, for example, that is seeking 8% growth on a base of $207billion in sales, needs $17 billion in new revenue a year from innovation to achieve that. GE will not tolerate fuzziness at its front end of innovation.
For some, fuziness is more about how to select projects from among the ideas generated at the front end.  There are many tools available to help managers select the most appropriate projects.  The best of those use some form of weighted linear model.
My advice: Create an innovation schedule.  Hold people accountable for generating new business opportunities.  Sharpen the focus, and reward teams that bring forward an exciting portfolio of current and future growth opportunities.  Accepting fuzziness in the front end is accepting slow growth.