The point is that you can make the Brute more complex without needing a UA.I mean... not sure that's more complicated than remembering that 19 is a crit and what you do when you crit.
But ok.
Still doesn't make it different from the Champion.
I mean, either one would be fine. But we definitely don't need 2 simple fighters.
Because the Brute mechanically and flavorwise does not do anything but have bigger numbers. In contrast to the EK which has magic that can perform many effects. IT doesn't even have a skill buff like the Champion.
You can damage, save bonus, healing and AC buffs complex.