I'm sorry to read that you are thinking of starting the D in the new year. Are you doing this for you or are you doing this in the hopes that by filing she will wake up?
I understand your frustration, but if she is in MLC, it takes a very long time for the depressive fog to lift. I know that you've stated you've dropped the rope and are done...but are you truly done?
Let me ask you this...if your wife had been in an accident and was in a rehab facility in a coma, would you walk away and not look back or would you continue to hope and pray for her, and yet, continue to live your life to the fullest while she's lying there? Would you divorce her because she's lying there in a coma and the doctors can't predict when she'll wake up and at the moment can't be an active participant in the marriage for the time being?
The reason I am asking these questions is that I want you to be absolutely sure that filing for a divorce is what you want and not just a knee jerk reaction to something that has been done, said or because it's the holiday season and you are feeling out of sorts because of your situation. I want you to really think about this and if you are absolutely sure this is what you want to do, then by all means do it.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.