I'm not sure that the wave form differences between planars and dynamic phones matter a great deal when each is less than an inch from your noggin'.
What my HE 400s do extremely well is make it seem like sound reproduction is an "effortless" task. The near-flat bass response possible is a great thing, sure, but I am not sure that dynamics do not typically achieve this as well, in certain applications (concert speakers, monitors, and so on).
I am inclined to attribute a lot of their desirable sound qualities to larger overall surface area. They can simply move more air, and will not work as hard to produce greater volume. Ever heard a 15 inch sub in a car? How about an 8 inch right afterward? A 15 is wasted in a car space, mostly, but the "ease" of bass reproduction can be really cool.
The planar's definitely have a lot more surface area. But it seems that, based on different frequency response curves I've seen, they can struggle in the midrange and treble frequencies - just like a big driver being asked to play at a higher frequency than it is optimized for.
I am probably totally wrong on this, but I open to all suggestions. The main issue is also, of course, the dynamics "piston" like motion and rubber-band like popping compared to the planars movement within a magnetic field.