Other than the insults, I agree with both of you. Wait, you said on facebook... are any of my players there? I have this EXACT scenario as a role play here on the Escapist- it's called Azure Wyrm and I would like more players! I'm actually doing an event on Halloween with it too...
Advertising out of the way.
Anyway, I wouldn't vote on loose dragons of mythical standards (it's possible to make, but would be potentially too dangerous, unless they're unable to breed, and only rich weirdos have them in fireproof habitats and wearing Invisible Fence collars).
If it was simply a cat's body (including claws, plus most dragons are based on cats), but with scales and a spinal fin from an iguana, but intelligent, loyal, trustworthy, and selfless like dogs, it could work and NOT be more dangerous than a dog- which is really just a tame wolf. Then again, the only reason dogs accept us most the time is because we, like them, are pack animals and they can be taught to accept us in their pack and consider us Alpha. If the dragon has non-pack instincts and behaviors, I still wouldn't want even something as simple as this made. Also it should have goat horns.
If I did have that I'd also go the extra mile and have its green color come from chlorophyll so it doesn't need to eat as much as it otherwise would. I'd also make sure it sounded right- crocodile. Screw it I'll also opt for giving it Pack Rat (collect shiny things) and Oyster DNA (pearls) so it could make its own dragon hoard.