I have a lot of respect for Jonathan Oppenheim, having read his papers for some time, and having met him a couple of times a long time ago, so no "obvious reasons to dismiss this out of hand". However I would estimate the odds of this model to be an advancement toward a more accurate description of merging quantum with gravity quite low. The main reason being that it is... not crazy enough. I remember reading the paper when it came out, and there was no wow factor there, no "holy ****, this is a completely new perspective, a unique insight!" And some kind of paradigm shift is most likely required to make progress on the problem that has been baffling the smartest people in the world for 80 years. For comparison, here are some at one time out there ideas in fundamental physics that did not pan out, at least not so far:
- particles are not pointlike objects but tiny rubber bands
- the universe is basically a moving picture
- when all matter eventually becomes radiation, time itself loses meaning, and the universe starts anew
That said, the point that "Gravity itself is non quantum" and that spacetime is emergent is a hot area of research, and is being attempted from multiple directions, some quite encouraging. Also, the analysis part of the paper, that is, why semi-classical gravity is a non-starter, is well worth reading, if you have the background.
Isn't that what he addresses in this section?