Sort of disappointed with this new feature. The crystal is a pretty boring looking 'building' and feeding a dragon up to level 15 doesn't really do much. They look exactly the same. It's just one big firapple consuming pit. I raised my fire dragon up to level 15 and it ate up a whole lotta food. More than a 100 thousand I think, and that's the lowly fire dragon. On top of that now that we can raise dragons up to level 15, that's going to be an excuse to make the battle arena even harder (in the name of balance) for those people who only evolve to 10.
I can understand how it would be a huge task to redraw every single dragon a new level 15 evolved design, but there is absolutely nothing special about a level 15 dragon's appearance. No glow, no aura, no trail blaze, I'm not even sure he got any bigger. They could have added some affect so that other neighbours can see all your hard work.
I don't really see any good coming out of this