Let the AssImp folks know about glTF.
...and us know about them :) I believe good collaboration could happen here.
We should have a separate fmk/library to just handle glTF output, so that it would be easy for third party to implement import for any format. I thought about this till the beginning, so splitting OpenCOLLADA / glTF export shouldn't be too hard.
Does anyone know the AssImp developers? They may be interested in glTF now as we approach a draft 1.0.
Now part of #456.