почему убрали зимние карты?

They were never intended as full-release maps. Although they offer a nice change, they generally don't meet the quality of PR maps because we lack a lot of the statics, sounds, textures, kits, etc. that would be necessary to do that. Thus they were offered as "holiday" maps... for fun. They won't be included as part of the core PR until we feel they meet our stringent requirements, but maybe this winter some servers will run them again.