Dan sucks on purpose

[BumblebeeCody]

Well firstly the guy who worked on the design for Ryu (Takashi Nishiyama) also worked on KoF and eventually came up with KoFs version of Ryu, Ryo as a joke. But then the Street Fighter team retaliated (a banter) by making a joke of Ryo and creating Dan. The similarities between the 3 are obvious even with their moves sets
(SRKs, QCB+K = variation of Tatsumaki)

Secondly Dan being a joke characters doesn't make him bad (especially in AE Ver.2012).