I think it is because aside from SAM, Dancer was the next job players were most excited about, and actually people only started to board the SAM hype train after seeing Yoshi P in a spiderman shirt and the Sam Raimi thing, i do not recall players talking about Samurai before this.
Not to mention that now having 2 dps over having 1 dps and 1 healer (or tank) does not make 100% sense. Hooray for having 9 dps jobs and longer queue times i guess?