I think this is for a couple reasons:I didn't plan to but I might just for the heck of it. Also the protagonist being silent in these games really makes me wonder why they don't just allow people to create their own character.
1. Soejima(the art director) likes designing a specific character to be the MC. They're supposed to fit within the game and have their own style.
2. The protags, though silent, do actually have their own personalities. You can tell from their dialogue choices. So they're designed to be a bit more than just a silent character.
Also plz finish the Nanako and Dojima links. Two of the best in the games.
ALSO also, watch Gurren Lagann you jerks.