... The historical trend is towards using uniform time units. It seems curious now that when the atomic clock was invented astronomers opposed calling it a "time" standard.
Well, it seems curious to everybody except Rob Seaman :-)
... It is much like the ancient Egyptians (IIRC) making the transition from sundials to water clocks. They had always marked out hours on sundials subtending equal angles, so the actual temporal length of the hours varied over the course of the day. When the water clock gave them an independent time reference, they were horrified that its uniform hours didn't match sundial hours. Much technical ingenuity went into mechanical modifications to water clocks to make them accurately emulate what went before. ...
Nice analogy. Ed.