It doesn't seem to me that Druid API is going to stabilize in the near future (if ever), because there are so many extension points and something is broken in every release. On the other hand, Druid is not Hadoop or Spark, which have applications API. Druid API for extensions, not applications. It is used by people who are closer to Druid development and fixing their extensions is routine.
With that, I think it make sense to drop "0." from the Druid version and call it Druid 14, Druid 15, etc.
