A reader of classy.dk proposes a risk index for business proposals as Investment/(Experience * PitchLength). The Delmore Effect suggests that it could be that a lengthier proposal is in fact an indicator for less desire to win in the proposer. So risk may in fact be greater if the pitch is longer.
But of course length of pitch could be an indicator of a poorly articulated strong desire (i.e. anxiety preventing the proposer from getting to the point) as well as a well-articulated weak desire (Jargon-heavy detailed analysis of what-ifs that would make sense one year into the businessplan but not in getting the ball rolling)