I also think a buffet is more work than a roast.
Is it not easier to stick some fresh herbs into a turkey, slather it in butter and roast it, buying in trays of prepped pigs in blankets, roasting veg and red cabbage from M&S and just heating them up?
If I was having a buffet on Christmas day I'd love a ham (way more faff than a roast though - boil it, take off skin, criss cross fat, glaze it, roast it etc.) Or some freshly baked savoury pastries (again, more faff than a roast)
To keep it really simple and work free, I think a brilliant cheeseboard (good cheddar, good brie or camembert, Stilton or Dolcelatte, roule) with fresh crusty bread, lots of types of cracker, grapes, fresh figs, quince jelly, good pickles and chutneys is a good bet. Add olives, mixed roast nuts, big bowls of clementines and christmassy sweet things like mince pies, baby stollen, lebkuchen etc.
Thats my favourite Christmas food - grazing on cheese and fruit and nuts.