First I thought this was about file caption in TV. This might therefor be a little off topic, but I think this is justified anyway.
I think there should be done more to the default caption code. Here is one example (let's hope I copied the right line from my backup document):
If(IsEqual([Media Type], Audio),[Name] - [Artist] - /([Album]/) // Rating: [Rating],If(IsEqual([Video Type], Series),If(IsEmpty([Name]),S[Season]E[Episode]/ (NP:[Number Plays]/),S[Season]E[Episode]/ (NP:[Number Plays]/) - [Name]),If(IsEqual([Video Type], Music Videos),If(IsEmpty([Artists]),[Artist] - [Name],[Artists] - [Name]),If(IsEqual([Video Type], Conserts),[Artist] - [Name],[Name]))))
This is a caption with my custom "Video Type" library field, and do not contain any Image or data caption yet. But I think something like this, that contains the Video, Audio, Images and data should be available as a default. This kind of captions should be easier to make with a GUI similat to those that have been made to other parts of MC.