Well, there is little doubt now. The latest White Dwarf image has the Sisters getting a new Codex, though one assumes, a digital one.
The Sisters will stand alone, not as part of Witchhunters, just as Grey Knights were pulled from Daemonhunters. So this will formalize and update that horrendous White Dwarf update. The two big things to expect:
1. All rules updated to 6th edition.
2. Warlord Traits
BTW, isn't it "Adepta Sororitas" NOT "Adeptus Sororitas"?
Nykona