Speaker designs changed when solid state amps became popular and power was no longer a big concern. Smaller enclosures, lower efficiency and much higher Xmax in the LF drivers. All of a sudden cones were moving a lot. Stopping them from moving was done mechanically, or electrically. Mechanically by surround and spider, electrically by the motor. If you are using a high efficiency large driver, with a low xmax, DF not such a big deal. But, if using a small driver, with a high xmax that is low efficiency, then you want high DF. The speaker has to be controlled and made to stop when there is no signal.
Like most things in audio, it depends.