Sculpted banners exist to make it less intimidating for tabletop painters. But I think every box should come with 2 banners, one with no detail sculpted. But I don't think GW really cares about people who are solely into the painting, but want customers who will buy full armies, and paint them quickly so they can buy new armies.
As for the banner, you could have him standing on a cracked earth, lava field type surface. Or, since it is a Tzeentch dude maybe not worry about it, they are magic. Or being the warhammer world just have it standing on a pile of skulls.