This seems like a natural progression to me. When the rotation of the earth was the most accurate period available then it made sense to use that as a reference

This seems like a natural progression to me. When the rotation of the earth was the most accurate period available then it made sense to use that as a reference. Now it is not and it doesn't. I think that in the future people will just use UT for anything where people have to coordinate activities. We can have a separate time scale for things we want to coordinate relative to sunrise and sunset. This scale will be able to be completely accurate based on location so we would abolish stupid stuff line time zones and DST. The result will be much simpler.