The Heisman Trophy, with a few exceptions, is given to the "best" QB or RB on a national title-contending team (despite the fashionability of the position, it actually rarely is awarded to WRs). If you aren't on a national-title contending team, then you need to be a QB or RB with otherworldly stats that push you over the QB or RB on a team that is a contender. This is how Lamar Jackson and RGIII won the award.
The problem for us Vols is that Johnny Majors and Peyton were 2 of those exceptions. And these were big exceptions, bigger than Lamar or RGIII winning it. Majors lost it to Paul Hornung, whose 1956 Notre Dame team went 2-8 and he still, to this day, is the only Heisman winner from a losing team. Woodson, to this day, is the only primarily defensive player to win the award, despite Peyton being the best QB or RB on a national title-contending team. There isn't a conspiracy against Tennessee to deny a Vol the award, but honestly I see why people feel like there might be.
I know people are upset about Shuler in 1993 as well, but honestly I feel like Ward deserved it. Numbers were better, and played on a better team.