Although I have no idea if people have these ideas already but here are mine.
1: Keep all 50 titan runes to level up your dragons instead of getting 50 for each dragon.
2: To be able to change the name of your characters and dragons at least one more time.
3: Add more variations of warpaint designs and to be able to change their color.
4: Add more than just 3 colors to use on a dragon when customizing it.
5: Add a button that allows your dragon to roar, like how you can make them breathe fire or get on and off your dragon.