If you are adding Eviscerators and Imagnifer to the squad, then you really aren't playing Sisters correctly.
The best composition is either:
-10 Battle Sisters, Veteran Sister Superior, Book of St. Lucius, Brazier or Combi-Flamer, Meltagun, Heavy Flamer, Rhino, Extra Armour, Smoke
or
-10 Battle Sisters, Veteran Sister Superior, Book of St. Lucius, Brazier or Combi-Flamer, Flamer, Heavy Flamer, Rhino, Extra Armour, Smoke
The current problem in the codex is the Rhino costing 50 points, extra armour 5 points, smoke 3 points, and search lights 1 point. On top of that, the Sisters of Battle Rhino has only one fire point.
That's all well and good, but they are still overcosted compared to the new codices troops.
IMO 11 points for a Sister, which is essentially a vet guard in power armour with bolter, is good deal. If they do bring Sister in line, they might bump the heavy flamer to 20 points, similar to IG one. But in return, I hope they increase the number of special weapons, allowing 3 Meltaguns.
As it stands they are too many points
IMO. They should be 10 points per Sister. Maybe an additional 10 for a Vet Sister. I would not be opposed to them having stubborn base.
Sisters aren't all that bad in current 5th ed. They only suffer in annihilation missions, lack or reserves, and not enough beefy vehicles against anti-range mech shooty spam.
I wouldn't say they are the worst list but they are a bottom tier army...probably bottom 3.
As it stands Sisters:
Aren't competitive-especially in the tournament circuit.
Aren't fun to play- they are confined to a gimmicky Rhino rush mono-build.
Aren't flavorful- as is stands, what do you see (if you even see them played?) Cannoness, Battles Sisters, Immolator, Exorcists, Seraphim, and sometimes Inquisitors (for sleaze factor), and Celestians
So if they can make the new codex either competitive, fun, flavorful, or any of the above combinations then it's a better codex. New models (which have been rumored) are a plus as well.