Trading off safety and performance in the kernel

The best outcome is going to be a tunable. Good or bad, the changing the default sync behavior will take years to be fully accepted, and even after all the major userspaces catch up, there will probably always be a few people who are stuck with buggy legacy userspace and firmware at the same time.

A tunable lets individual users choose when they make the transition. Look how long it took for atime to stop being the default to get an idea how long such a change can take.

There are always kernel regressions and crashes that lose some uncommitted data. We don't run filesystems in sync mode all the time because the performance (and wear and tear on disks, rotating or otherwise) is a price too high for the negligible benefit of less data lost on a crash. At some point that sync on suspend *must* go away.