Weapon skins would be rather meh, because of the game's poor (in terms of quantity) lighting. You wouldn't be able to differientate between each other easily, so everything would look, more or less, the same.
I'd love a Steyr AUG, it's my favorite gun. I know it doesn't exactly fit the RE universe, for some reason it feels too militaristic while RE is not of such type, but I'd love to see it in the game. Magnums, yes, definitely want to see some of those included. I think M82A2 anti-material sniper rifle is already in the game, but if I'm wrong, I want to see it along with the DSR-1 sniper rifle. They look so intimidating, and they pack a punch.