I think there is some confusion here. New mastery is ready to train for all. To get Skyscale new way you actually need to fully level up new mastery first as part of the collection, before getting Skyscale available in old maps. People who got Skyscale old way don't need to finish new collection, unless they want to finish special mission in Vault (but it takes like 1 day if you have crystals), and they still can level up new masteries and fully use all of the new skills.