There are DS-style buffs already in the files corresponding to each one of the tier 14 raids. Blizzard is on the record saying that the DS buffs were one of the things they feel like they got right in that raid, and the model will be used in the forseeable future. This isn't a matter of if, it's a matter of when. Therefore, asking when the first stack is going to activate is not a request to nerf the place. That's going to happen anyway. What it is is a request to know what the deadline is for a pre-nerf kill.
Personally I'd wager it's happening in early January for MSV, and later for HoF and ToES, but those are just guesses, since they haven't released the timetable yet.