edit: I should preface my post below with the acknowledgement that I work for a Fortune 500 company that is amongst other things, a supplier of materials and processes to the semiconductor industry, including mobile handset divisions of companies that we all know and love and some love to hate on. I'm not a EE, but I did sleep at a Holiday Inn last night (kidding) and I hobnob with a lot of MEs and EEs in the semi industries (not kidding). I'm an analytical chemist, FWIW.
I don't claim to know the answer to this specific question, but I do know this: not all LTE radios are created equal, nor are their power amplifiers and RF filters. It is perfectly conceivable that the combination of the above-mentioned chips (and likely additional chips) could have had a glitch when assembled in the way that they were in this particular phone, whereas some Moto chipsets might be a proven quantity (I don't know if the Bionic's chipset is the same as the Xyboard's). Like I said, I don't now the real answer, but I stand by my statement that some chipsets can behave differently from another, even though they are supposedly built to a specification.
Furthermore, the firmware that controls the communication between the chipsets and towers absolutely will be different for different makers and their corresponding chip-level design choices. I am hoping that if it is truly an LTE-related issue, that it can be resolved at this level.
Finally, not responding to you Early, but to others that claim "there are already Verizon GSNs out there and they don't have any problems, so it can't be an LTE issue.": wrong. It can very well be a regional thing. If anyone thinks that all LTE towers are absolutely identical, down to the switching center in every region, I would wager a very, very large sum of money that they are dead wrong. If Verizon wants to not have another Thunderbolt or Bionic (or whichever other phones were having problems, I know the Bionic was one of them) customer support/reputation problem on their hands, they are going to want to make sure that it is playing as nicely as they can get it to with their LTE systems in as many regions as they deem acceptable to them. This is consistent with the email that was read to me while at a Verizon store last Friday, which went along the lines of "This phone does not yet meet Verizon's high standards for quality.". This was the reason given to me for the delay of launch.
Now, Verizon may be blowing as much smoke (and/or have political motivations that are beyond our knowledge) as the general feverish population in an internet forum such as this, but that may or may not be borne out in the weeks and months to come.
All that said, I wish Verizon would just issue a press release with some information resembling an explanation. It would calm a lot of nerves and satisfy many customers until the device is actually released. Clearly, they do not completely understand the customer profile of the person that wants to buy this phone.
All that said, WHEN AM I GONNA GET MY NEXUS???!!!
Sigh.