Thanks for providing the code. It would be even better if you shared everything as a GitHub project that's easy to clone and build, contains the CSV files, and also the specific parameters you're sending into program, like batchSize.

You didn't mention how slow is slow. What is the ingestion rate for vertices, properties, and edges? Some more concrete details would be helpful. What does your HBase deployment look like?

         * Note: For unknown reasons, it seems that each modification to the
         * schema must be committed in its own transaction.

I noticed this comment in the code. I don't think that's true, and GraphOfTheGodsFactory does all of its schema updates in one mgmt transaction. I'd be interested to hear more details on this scenario too.