"I can't claim to be a "smart GM", but I've never had a problem with Bricks purchasing Martial Maneuvers in my campaigns. "Brick" and "Martial Artist" are nothing more or less than Special Effects for how your character meets the campaign's guidelines. I don't believe a character should ever be punished for choosing one special effect over another, except to the degree which they have chosen to be punished by placing appropriate limitations and complications on their character.
The issue stems from inconsistent enforcement (or a complete lack) of campaign guidelines; not with Strength, Martial Arts, or any other source of Added Damage specifically. According to the Character Ability Guidelines Table, a Standard Superheroic Character is supposed to be dealing between 6 and 14 DCs, using no more than 80 APs. It doesn't matter how the character meets those standards, so long as they do, they'll be relatively balanced (even if they happen to be a Brick who learned Boxing). Balance issues only start to arise when one or more characters significantly exceed whatever Guidelines that other players (including the GM) expected/trusted them to follow, or when one or more of them significantly falls short of said guidelines I suppose. Any character concept can be broken if the GM doesn't properly audit them to ensure that their abilities fall within an acceptable range for the campaign being played."
I agree. No character should be penalized for trying to create their character in whatever manner it needs. It's an entirely different matter if the player is deliberately trying to monty haul their powers, causing problems. With the justification used prior, bricks shouldn't get Blast attacks because that's a workaround for them having to be in HTH combat to wallop a villain with their Str, which of course is ridiculous. It is up to the GM to help the player create the character concept wanted by the player, yet to make sure the character is not overly powerful in some manner. This is why, in the campaign I'm in, all characters created are checked by the GMs and when a new skill or power is wanted, a round-the-table agreement by all players and the GM is given. This way, the GM and the players are all aware of what was gotten by a character.