Maybe it is a good idea to collect all the really cryptic errors and what bug they are actually pointing to?
For example I encountered this one a few times now:
ember.debug.js Error while processing route: translations.edit Assertion Failed: Passing classes to store methods has been removed. Please pass a dasherized string instead of undefined Error: Assertion Failed: Passing classes to store methods has been removed. Please pass a dasherized string instead of undefined
And it actually means: You are trying to parse a embedded object, please add a Serializer and extend the EmbeddedRecordsMixin for object