Not going to lie-- I skipped to the baby dragon first! ;)
I would move. The new barn sounds fine, and with the flexibility of a winter paddock if you are *truly* that worried...
That being said I don't thing stalling in a 12x12 overnight in the winter is so bad. My boy has an in-and-out (stall attached to a little paddock/run) and he prefers to lay down/roll in his stall on cold nights. I know this because I leave a bay horse in the evening and return in the morning to find a rare, bedding-chip marked appaloosa... I swear, he pulls out half the bedding into his mane and tail.
Anyway! I say a quick, quiet transition to a new barn is in order. :) And if the old BO gets fussy? So long as you are paid up to date and within the confines of your boarding contract, I say kill her with kindness as you walk out the door!