I agree with you but it may not be practicable.  When you ask a question and you get say five answers you can judge the best answer.  How would you lump and rate say five questions?  Perhaps you could get one point for rating any question as "Good Question" giving the author a point too.  Please suggest that to Yahoo (see bottom of point page that invites suggestions).  You deserve the credit.  Good luck.
Dontcha think we should be able to vote on Best Question?