Well, we're now long enough in that I actually have a handle on it so can give a meaningful answer
TBH, remarkably little has changed - sometimes to the point that I'm wishing it had. But there's a few bits, so here's my Sororitas perspective:
-I miss the Template. Not the blasts, those were rarely reliable anyway, but the flamer template. I need the (Heavy) Flamers to reliably inflict horrific casualties on huge mobs, and they just don't anymore. Between the mere 1d6 hits regardless of unit size and the fact that there's no AP on them, even a Heavy Flamer will kill only about 2 Conscripts (3.5 avg hits, 3+ to Wound for 2.333 avg wounds and 6+ save left for 1.944 unsaved ones) - which rarely impresses the other DOZENS. Never mind that a lot of assault armies can charge with confidence from beyond 8" where the Flamer won't even get Overwatch now.
-Speaking of template weapons, Hand Flamers. Now 1d3 hits at S3. Who thought THAT was worth any points? I'll stick with the free bolt pistol.
-The Immolator's got it right, though. Assault 2d6 Immolator Flamer at 12" solves the overwatch issue and makes for a very good transport with both speed and firepower. It they're carrying Dominions they get the scout move 12", into Turn 1 normal movement for another 12" + advance, 1d6" and can still fire with a 12" range for autohits... yeah. Good stuff. Immo spam a thing again.
-Other side of Sister weaponry, the Melta. Used to blow up vehicles with ease, but now... Only wounding T8 heavy vehicles on a 4+ leads to it being too easy for them to whiff completely, I feel. Worst I've seen was a Plagueburst Crawler that took all of 5 wounds over the course of a 6 turn game despite being targeted by at least 4 in-range Melta weapons each turn.
-Repentia and Penitent Engines. Problem children of the codex for a couple editions now, and no real change here either. Repentia barely rate a meh (which is, admittedly an improvement over the Nope they were in 7th). They're now pretty good in melee on the charge, but they're still T3 and only have a 6++ to keep them alive... so that's just not happening. Penitent Engines are probably worth taking if you spam nothing but, yet only one or two make for a lousy addition to an existing Sisters force.
-Fast Attack is still where all the really good stuff is. If you see a Sisters force in anything but an Outrider detachment, something weird is going on.
-Acts of Faith are good but don't scale well. Sisters are probably a better allied force than army of themselves.