Adapting the plan at runtime seems like the most universal solution for optimizer edge cases and is already implemented in the big 3.
If you think about it, the adaptive mechanism doesn't have to be perfect to have a lot of uplift. Even coarse grain detection and starting from zero can make a huge difference if the alternative would be a query burning up the server for hours and a failed batch job.
Adapting the plan at runtime seems like the most universal solution for optimizer edge cases and is already implemented in the big 3.
If you think about it, the adaptive mechanism doesn't have to be perfect to have a lot of uplift. Even coarse grain detection and starting from zero can make a huge difference if the alternative would be a query burning up the server for hours and a failed batch job.