I prefer to get away for Christmas and New Year but have run out of breaks to choose from! This year I did get away for New Year and had an enjoyable time, but it did especially highlight the first of my points.
If it is a city break Christmas and/or New Year the hotel needs to be central - to the sights, to cafes, shops, bars and restaurants. Away from the Mediterranean, in the northern hemisphere it is winter, therefore liable to be cold, wet, windy, with short daylight hours. Not the time to experiment with unfamiliar buses and trams etc in free time, or standing around waiting to be picked up by a coach.
My second thought is regarding coastal breaks - the hotel needs to be actually on the coast near the amenities - not isolated (unless perhaps it is an all inclusive spa type break) and not in an area of the town where there are few facilities.
Group size is important to me. I was delighted to see a group of 18 quoted on a recent review and horrified to see a group of 69. I was with a group of 40 Christmas/New Year 2017/18 and found this too many - too many to get to know, for getting on and off the coach, for guided tours, queuing for toilets in the cold is no fun, for restaurants and cafes.
Obviously the majority of travellers are there to have a good holiday and will make the best of the circumstances, but the better the arrangements the more enjoyable the holiday and the better likelihood of good reviews and repeat bookings!!!
Having had a succession of "cold" year end breaks perhaps more warm/sunny breaks would appeal? Alternatively some guaranteed snow - if only!
Looking forward to more reviews of the recent Christmas/New Year breaks - it is good to have several different reviews - whether good, bad or "curates eggs".
Wishing you all "happy travelling" for 2019.