This subject has been brought up many times. The big thing to remember is that the Heisman is a private award in which the winner is decided on selected voters. The voters range all over the map as to who is eligible. Therfore performance is always going to share the driver seat with exposure.
If I remember right, Troy did very well his second year for Heisman in votes when it came to midwestern and west coast ballots. But due to lack of exposure since our team could never wins/get talked about, the east coast voters gave him almost no respect. Therfore he lost. In the end the trophy is what we as fans make of it. The award does not go to the best athlete but the best marketed athlete. That is why sports writer Stewart Mandel feels that there is a curse behind the Heisman when going pro. The best athlete never got it in the first place! Although Troy's second attempt had some incredible competition to fend off.