I like the way it looks now. It doesn't look amateurish to me. The other site you mentioned looks "businessy" in my eyes, with too much (generic) website personality; this looks intellectual and understated, like a simple stage for the personalities of the posters to come through.
That said, if the goal is to increase site awareness through branding, changing the design would help. If the goal is to increase site awareness through distinguishing it as different, I'd say stick with the basic (or a similar basic) design, which already does this.