I would suggest Antalya or the areas surrounding Antalya for the best weather at X-mas time... no one can predict what the weather will be like at any time of the year....but..the low touristic time in Antalya is great...and a wonderful way to visit some of the wonderful historical areas nearby..
Great time for sightseeing the historical sites if the weather is bright and sunny..it's not too hot and you're usually the only visitor!
lovely sunny days or down pours of rain..who really knows...last year however we had very little rain over the winter and for the most part..
as for hotels it seems to me that the AI resorts aroud Lara beach get the best ratings..