Personally, I think it is a bad idea. The day should be about the newly weds, and the newly weds only. The celebrations of a New Year will detract from the actual purpose of the day.
I went to a wedding not so long ago and the best man and his wife had just passed the "safe" three month pregnancy period. They kept quiet becuase I know realise they didn't want to take any limelight away from the bride and groom. New Years eve may have the same effect.
Also people may be all fested out due to Christmas and/or have made other plans than a wedding