/eureka! I figured out Brute Justice's true inspiration! Maybe!
He's a big shout-out to Transformers, not Voltron. While his color scheme is a bit indicative of a general shout-out to combining mechas, it doesn't match Voltron's configuration.
I don't know the names of the individual robots that make up Voltron, but his color scheme goes like this:
Black (Main Body)
Green (Right Arm)
Red (Left Arm)
Yellow (Left Leg)
Blue (Right Leg)
Brute Justice is set up as such:
Green (Main Body)
Red (Right Arm)
Blue (Left Arm)
Yellow (Right Leg)
Green (Left Leg)
Doesn't add up. However, while his color scheme doesn't match, Brute Justice is a giant shout-out to the Decepticon combiner Bruticus and his components, the Combaticons. The proof is, as such...
Bruticus (Gestalt)
Onslaught (Main Body)
Blast Off (Right Arm)
Vortex (Left Arm)
Swindle (Right Leg)
Brawl (Left Leg)
Brute Justice (Gestalt)
Onslaughter (Main Body)
Blaster [Off] (Right Arm)
Vortexer (Left Arm)
Swindler (Right Leg)
Brawler (Left Leg)
The colors aren't exact, but the names line up.
... I'm not the first person who noticed this, am I.