But the change needs to be made soon if you want to minimize breakage when people update, and the fact that dub has been getting some attention it the main D newsgroup will likely lead to it being used more soon if it hasn't already (that's how I found out about it).
We thought an automatic conversion from JSON to other formats should be easy because it is a data driven format. Meaning it should not be a problem to replace the format at some day, maybe having dub accepting both for a while.
Best regards,
Robert