Since I don't know enough of your story yet -- the idea of a phone call gives me pause. When did you last have an in person visit, a phone call or any kind of contact?? And how did she react? What is the tenor of your relationship now? Are you two "friends" and on cordial friendly terms??
If you have a nice relationship with her -- and your in person or phone calls go well -- then I say GO FOR IT!!
But, if she isn't thrilled with in person or phone calls with you -- then I think sending her an email or some other breezy contact is a better choice and quite fine.
I think as long as you haven't been in some constant pursuit of her -- using any and all excuses to contact her -- then a New Years wish is lovely.
Sometimes I think we all over think things. We all should work towards coming to a place where we just treat and deal with our spouses as we do any other "friend."
Again, it really depends on if your overtures of friendship are well received.
But I always err on the side of kindness. And I think wishing someone you love a Happy New Year is loving and kind.
