All I know is that Dan is just a mock-up character for the Street Fighter series.
Actually, he was designed more as a "Take That!" to SNK and their Art of Fighting series. One of the original designers for Ryu and Ken eventually left Capcom and joined the SNK bandwagon, where he went on to design Ryo and Robert (who allegedly, were closer to what he wanted Ryu and Ken to be all along, any way).
Of course, Capcom didn't take all that lying down. Dan started appearing in art (usually after being beat up by Sagat), before finally making an appearance in SFA1. Despite his intent to be a joke character, he actually ended up being one of the BEST characters in that game. And so, Capcom had to actively put out an effort to make him a butt monkey ever since.
