I've been watching this network issue too. A couple users at XDA that were actually able to talk to someone at Asus says they have no intention of adding VoLTE compatibility in the U.S. on the ROG II. Data will still work, leaving open the option for something like Google Voice (my only option either way on Verizon), but it has its own tradeoffs, especially for making 911 calls. So for all intents and purposes, this would become a hand held gaming device disguised as a phone.
I still want one, but it's just too hard to justify it at that price right now with their lack of communication and apparent refusal to make this fully compatible with at least one U.S. carrier. So for now, I'm just going to repair the camera on my V20 and just keep an eye on this. Or maybe go with the Razer 2, since that's actually on Verizon's approved BYOD list.