Eeek!

I think what jeebin means by making 'em more complex is keep the style you got, but at the same time, expand it a bit by trying different things out. Try adding a top and bottom border in your sigs for example. Not a complete border, but a simple top and bottom one.

Remember too that borders look different on various sites.

Personally I like your last one, but the spatters kinda look funny to me. Try to change the blending modes on 'em and see how that looks.