I think there needs to be more rewards for reaching onyx and champion rank. Like a emblem or some harder. And when you reach champion it should say it by your name. Only way you can show it off is by going up against people which are probes champion anyway. Or unlock and onyx or champion skin on the pistol. A reward for completing the campaign on legendary solo like some armour.
I do agree they needs to be something for Onyx and Champion ranks. Maybe a pistol/BR skin for Onyx Swat. Stuff like that.