Use a diagonal composition
When making a dramatic splash like this, do not place the characters so perfectly vertical as you did here. Something that is vertical implies steadiness and calm: a no-no for an intense scene like this.
Right. Which is eaxactly why....it....IS a diagonal composition, heh. You're missing that a composition is not JUST about characters. They are vertical because the entire background is on a strict diagonal slant.
When composing an art scene---It's important to remeber that your subjects should be off set from your stage/setting/background. The flow of the scene comes from the slant of the background as they freefall, see? If I reversed that picture and had THEM slanted but the background vertical, it would be compositionally unpleasing because the cityscape is nothing but right angles and lines.
But since Stryker and Bison are Organic (built from curves) it means they can be situated however and it will *usually* work.
So while on the one hand, you have a valid point, your suggestion wouldn't work in this setting because again--composition MUST factor in your background. To have the whole image slant with no separation of focus and subject is never a good move.
Holy crap dude and I just watched Exiles 3 too.. your artwork is amazing. Seeing this definatly makes me want to draw more, and get better at it.