I thought impedance mattered with planars but after someone told me it didn't I tried it out on my Lcd-X and Teton and the X sounded great. Teton has something like 100 ohm output and X is only 20 ohms so I think the Lcd-4 should be good to go on almost all amps as far as impedance is concerned.
The fact that planar headphones have, essentially, flat impedance means that the damping factor is less of (or not) a concern - and that's what you seem to be talking about.
The effect of impedance on amplifier output power is unchanged regardless of the driver technology. Double your impedance and, generally, you're halving your realized output power (or worse, depending on your power-supply design etc.).
Then there's a 3dB drop in sensitivity ... which means you're going to need more power to get to the same SPL ... a bit of a double whammy. Couple these effects, and an amplifier that had sufficient grunt to do a good job, with useful headroom, with the "old" LCD-4 may struggle or have insufficient headroom with the "new" driver. I wouldn't see it being an issue with my Ragnarok, but it might well be for my WA6.
I'm an Audeze fan. I'm in favor of continuous development. I still think this is a pretty big change for a $4,000 headphone, particularly so early on. At that price I want to know what I am buying is properly sorted. Unless Audeze are going down the Ferrari FXX route here that is ...