If he wanted to accomplish in WWE what he did in Mexico:
"It's shocking WWE never did more with my image. It's an image that sells more merchandise than many wrestlers who've been in the WWE for years. My action figures, my shirts, sell more than many of the wrestlers who have been in WWE for years. In December, my merchandise was the second best selling only behind John Cena. I read some of the comments on WWE.com that said why isn't Sin Cara in storylines, his merchandise sales are only behind John Cena's."
It's hard to place the blame only on WWE though. For whatever reason, Sin Cara wasn't clicking in the ring or with the ring. They hyped his debut, had an evil version of himself to feud with and gave his matches special (but annoying) lighting. Where it went from there was on Mistico and he never really delivered.