Honda pulling out is completely understandable, and I think F1 should sit up and listen. The dynamic simply won't work with three engine manufacturer teams and the rest being customer teams - especially when Red Bull is a customer team.
It might be radical, but I'd prefer to see F1 return to a simpler naturally aspirated V10 ICE only power unit, perhaps with a completely separate (and simplified) system for brake energy harvesting and short-term energy deployment (exiting corners).
We have formula-e let's make F1 more accessible to niche manufacturers.