I think the main issue with Dragons may be because, they're Dragons.  I mean how do you ignore a giant lizard flying around that can turn cities into dust. 

[@Nightknight] I'd play around with the idea more, get NMS and Ded involved in the process. I think if your Dragon wasn't super powerful all the time and had to follow similar Rules as the Greek Gods do, then maybe he would be accepted. If his power is limited or if he couldn't act in his more powerful Dragon form and had to rely on a weaker human guise. I'm just tossing around ideas.

If Dragons are super powerful and wholly iconic as Dragons. Then making them appear less could get then accepted.