The rule that requires hunters to either pick applying for a trophy species (moose, mountain goat, or bighorn sheep) or deer, elk, and pronghorn was implemented to improve drawing odds for moose, mountain goat, and bighorn sheep. By reducing the number of people that apply for any one species, the better chance an individual has to draw. Allowing everybody to apply for any and all species would reduce everybody's chance of drawing any given species.. While drawing odds for any of the trophy species are relatively difficult, Idaho is often reported as having some of the best odds of drawing in the west for one of these species.
The Idaho Fish and Game Commission did review potential changes to the controlled hunt system a few years ago, but were primarily focused on addressing what could be done to improve drawing odds, including the option of only allowing an individual to apply for 1 species. Ultimately, the Commission did not make any changes in part due to the wide diversity of opinions held by sportsmen over what type of controlled hunt drawing system was desired.