I would love to see a system where upon reaching certain milestones as Predator or FT you are rewarded with exclisive items/cosmetics/trophies. Like maybe 10000 claims or 1000 captures pred bodies. Or difficult nontimed challenges.
New animal skulls like puma, lion, bear, maybe primitive human skull, as well as alien beasts similar to the ones on the trophy wall of Predator 2.
A trophy wall could also work to show off milestones and feats.