A dragon hatchling's color is based on what it will hoard during its life - and its parents don't know the color.
So, what if a dragon's color indicated what it will want to hoard, which could include abstract things like experiences or physical things like art? And if the parents don't know what will come from the egg until it hatches? And actually doesn't MIND if it's a different color, as that means they won't be trying to hoard the same thing? This means that no dragon is innately 'evil' or 'good', but how they go about hoarding their treasure indicates whether they are shaping more towards Tiamat's or Bahamut's ideals. Having chromatic = bad and metallic = good always sat wrong with me after reading FASA's take, because basically a dragon is to humans as we would be to mice that suddenly learned to talk (but got no smarter). Sure, some humans would still treat the mice as vermin and some might try to interact with them, but overall we live so much longer, are so much stronger than individual mice, and would find it nigh-impossible to actually