Metadata configuration is critical and the you must be careful while rolling out the updates to the production.
The user being used to create the metadata also has a bearing on the successful import of the metadata version given the version type is "ATOMIC". Each metadata entity is associated with a "User" object. If this "User" reference is missing while importing (for ATOMIC), the import will fail at the validation phase itself. For metadata versions which are of type "BEST_EFFORT" it should be alright. The point here is, the user that creates metadata also needs to sync down to local instances in order to successfully import the metadata given its of "ATOMIC" type.
It is recommended to keep the metadata versions size small and logical.