I think it honestly depends on the person and their personality. After all, with semblances and personality being outward expressions of a person's soul, there is an inherent link. More bizarre semblances are likely going to come from people with more bizarre personalities (or at least bizarre interpretations of a person's personality). Personally though, the simpler semblances are easier for fans to believe to be plausible and they're more able to coincide with a person's personality. The stranger you get, the more hoops you have to jump through not only to create a sustainable personality, but also to sell it to the fans. After all, there are a number of things that we still don't understand fully about the concept. Why make things more complicated?