@vlaviron @octachron, I would be very interested to read what you might think of the proposal to use an opam config variable so that individual users could more easily enable higher optimization levels for an entire switch. I have not had a chance to test this approach, but presuming that it plays nicely with opam, would that step already be too far in your view? It seems to me to be premature to change the default, but I also think that it would be beneficial to make it easier for people to test with a whole switch that is as highly optimized as possible.
It also seems possible that the optimal point on the compilation time vs produced executable speed might be different when building dependencies in a switch versus direct compilation of a project. That is, at least hopefully, we compile each library in each switch rather less often than we compile the projects we are developing. So it may make sense for the default when opam is building dependencies to opt for a higher optimization level than the default that is set for builds in the edit-typecheck-compile-debug cycle.