How was Gaga "not dark"? It wasn't extremely dark, but neither was Rihanna's. The Telephone and Alejandro videos had "darker" themes/imagery than the RR videos.
Rihanna's "dark look" always seemed too manufactured and just trying to cash in on the incident (which is quite cheap and tacky imo). She pulls it off well because of her good looks though.
But I mean, have you guys seen the Fame commercial...?