Robin Hanson criticises the notion of the Long Reflection in this article.
Some excerpts:
In our world today, many small local choices are often correlated, across both people and time, and across actions, expectations, and desires. Within a few decades, such correlated changes often add up to changes are which are so broad and deep that they could only be reversed at an enormous cost, even if they are in principle reversible. Such irreversible change is quite common, and not at all unusual. To instead prevent this sort of change over timescales of centuries or longer would require a global coordination that is vastly stronger and more intrusive than that required to merely prevent a few exceptional and localized existential risks, such as nuclear war, asteroids, or pandemics. Such a global coordination really would deserve the name “world government”.
Furthermore, the effect of preventing all such changes over a long period, allowing only the changes required to support philosophical discussions, would be to have changed society enormously, including changing common attitudes and values regarding change. People would get very used to a static world of value discussion, and many would come to see such a world as proper and even ideal. If any small group could then veto proposals to end this regime, because a strong consensus was required to end it, then there’s a very real possibility that this regime could continue forever.
While it might be possible to slow change in a few limited areas for limited times in order to allow a bit more time to consider especially important future actions, wholesale prevention of practically irreversible change over many centuries seems simply inconsistent with anything like our familiar world.
Hanson also refers to another article which is critical of the Long Reflection by Felix Stocker.
While Hanson is correct that the Long Reflection is rather dystopian, his alternatives are worse, and his "Age of EM" gives plenty of examples from a hypothetical society that is more dystopian than the "Long Reflection".
Hanson's scenario of "a very real possibility that this regime could continue forever" is certainly worrying, but I view it as an improvement over certain alternatives, namely, AGI destroying humanity, severe values-drift from unconstrained whole brain emulation + editing + economic pressures, and resultant S-risk type scenarios.
So I don't agree that a Long Reflection is worse than those alternatives.
More speculatively, I think he understates how prevalent status-quo bias is, here:
"the effect of preventing all such changes over a long period, allowing only the changes required to support philosophical discussions, would be to have changed society enormously, including changing common attitudes and values regarding change. "
Most of human history is extremely static relative to history post the Industrial Revolution, so humanity seems well-adapted to a static society. There are substantial political movements dedicated to slowing or reversing change. The average human attitude towards change is not uniformly positive!
You 'll also need to add increasing good outcomes, along with decreasing bad outcomes.