With the possible exception of Live Action stuff, characters are never 'incidentally' bald; characters are built, and important characters usually undergo several design revisions. Even in Live action, actors are selected based on what the casting calls for. None of the design or costume tropes cause or make the character to be stronger — Go Nagai sideburns are very seldom spontaneously grow from hot blood, and red hair follicles rarely burrow into the aggression centers of the brain. They're visual shorthand to apply certain conceptual archetypes to characters by showing, without having to explicitly tell the concept.

Take Lordgenome from Gurren Lagann for an example. He's built as an archetype of extreme stereotypical hotblooded manliness; that's his character, and there are very few parts of his design that do not reflect this. His baldness is part of that: he could do the same acts if he had shoulder-length locks of flowing hair, but he'd not look like a bodybuilder mixed with a wrestler.