I think any advantage of having more people to look for the disc is less than the other types of differing conditions that players face. These include weather, cardmates, delays, camera pressure, laxity of enforcement and on and on.
The way to deal with these is to have the players who are most nearly competitive with each other playing at the same time and on the same card. As long as each player is measured fairly against the players who are performing a little better or a little worse, then by the transitive property of inequality we will get the correct ranking.
And that's what a tournament is supposed to do. While it would be nice, we don't really need to measure the exact absolute difference in performance between the best player in the tournament and the worst.
As far as rules changes, one that would help would be to eliminate the needlessly double penalty for lost disc. Instead of adding two to the player's score and make them throw again, we could just add one to the score and make them throw again. Then, any advantage garnered from a preferentially-found disc would be reduced by a full throw.