Half-orcs. Half-ogres. Half-giants. Nephilim. Lizardmen. Minotaurs. There's always the impulse in fantasy roleplaying games to let the players take on that role so familiar from the superhero comics ... the big, dumb, straightforward aggro machine.
This leads into the balance problem. The brute kind of character is strong in combat ability and resilience, but weak in subtlety, strategy, restraint and charm. (And in intelligence, wisdom and charisma, but to be fair, those are pretty much dump stats for this kind of character.)
Ultimately, to be true to the character type, the player has to play dumb, impulsive, and crude. Restraining a mechanical advantage with a roleplaying restriction doesn't work for paladins, and it doesn't work for this type. And like with paladins, when the player does take on the brute's roleplaying burden it's often to the detriment of the party (see below):
So although I'm not sold on allowing the brute type character class in my race-as-class world, this did get me thinking on how I'd implement him. First, I'd make the brute rare. For example, you'd have to score below 12 on INT, WIS and CHA, and below 9 (penalty territory) on at least two of those stats; and I allow 3d6 in order with only one switch. Then you would get +2 on STR, hit dice d6+1 (1 less bonus point than a standard fighter), and an extra hit die on character generation. Its hide would count as leather armor but would have to have custom armor fashioned for it to get any more protection. The class would have no special powers, no feats, unable to even handle a bow, nothing but a pure tank. Oh yeah, and you could choose among a variety of options; basically any bipedal creature without special abilities and 2-3 HD in the wild; lizardmen, gnolls, ogrillons for Pete's sake.
The good grace of the Old School approach is that you can play this guy like a Machiavelli, or Beast from X-Men, because his powers and stats ultimately don't circumscribe the guile and problem-solving the player brings to the table. Might be something to try, anyway.