December skiing

Plenty of it been falling early already this season

Don't book now, wait till season actually starts and snow falls. I flew into GVA yesterday and Alps didn't look very white, only mountain tops, freezing line is currently close to 4000m. December is dead anyway, so you shouldn't have issues with finding accommodation anywhere.

I've skied Tignes/Val D'Isere in mid December many times, never had a problem with too little snow, only too much closing the lifts!

^^^ You must have been lucky then. Not every December is the same and last December while certainly skiable was definitely not worth a trip, even higher resorts with glaciers struggled. This summer glaciers also took a big hit as it was too warm for overnight freeze. Over 12 years of living and skiing here from December to April I have seen all sorts of starts to the season, from amazing to dreadful. Sometimes some resorts do better than others, sometimes early season conditions are uniform across the Alps. But getting accommodation won't be difficult in any case as many people might be out of annual leave by December or saving themselves till Christmas. Makes sense to wait before booking.

i think best skiing is in bansko