Batch Rendering is quite difficult to handle, especially in Automated System by the Engine as opposed the Developer.
I'd actually say that in
most Scenarios... the Batch and Draw Calls are going to be identical., as what is available to Draw is going to have a Unique Draw State; thus require being a Unique Draw Call.
This said Batch Calls actually do have their own overhead., meaning you actually DO NOT want to use Batch Calls unless you can guarantee what you've included in said Batch can be dispatched as a Single Draw Call because it has the same Draw State.
In essence I'd usually recommend Particle Systems are excellent candidates for Batch Draw Calls., and this is why these can have exceptionally good performance with Millions of Sprites On-Screen; where-as handling Millions of Sprites Manually; well that's going to be less ideal.
Now I think what would be useful would be "Instance" Commands., which would return an InstanceID... along with "AddToBatchGroup( )", "RemoveFromBatchGroup()" and "DrawBatch" Commands.
As this would also allow a breakdown of what can and can't be done with Instanced Objects / Sprites / etc. but also provide Control over Batch Processing.
Mind this said... honestly I don't think these are exactly the most important features improvements to focus on.
They'd be nice of course, but AppGameKit is VERY lacking in certain respects that there are other things I'd prefer to see to added / extended / improved / etc. first.
