Nice to see someone agrees with meFirst off I'd like to thank everyone for all the encouraging words! It really means more than you guys know.
Second, @Kennedward, that would be awesome! Unfortunately, TL has previously expressed their concerns on weighing down the hardware, which would potentially turn away many players on older/lower end devices; so while I would also love to differentiate level 15 dragons, it might be too much of a drag performance-wise to add in new particle effects to every dragon... At the same time there's no way they would be willing to go back and create level 15 evolution models for all 550+ dragons, so they've sort of dug themselves into a hole on that one. The best I could come up with is a quick low-opacity color overlay effect.
Basically dragons could attain slightly altered colorations upon reaching level 15. These alterations could also be dependent on the dragon's primary type, for example lighter types like red, yellow, white, pink, and rainbow would receive a relatively lighter coloration while darker types like purple, blue, black, and cosmic would receive relatively darker ones.
It shouldn't be too much work in the art or programming departments and would offer players a more or less noticeable way to show off their level 15s. But boy, if they would be willing to add it, I sure would love a flashy-sparkley-aura effect.