Ok, I realize I am probably opening myself up for flaming but I've had some time with the new Codex and I'm not sure I am worse off as a SOB player.
Before the negatives start, I want to make clear I am talking pure SOB. The theme for my army was to use only women. That left out priests as well as the various inducted guard, inquisitors and retinue, etc for the most part. I understand that may not the optimal way to use the Witchhunters Codex.
So one of the complaints is limited build options. If you only use Sisters then the build options were limited before.
Another complaint is the uncertainty of faith points every turn instead of being able to build in such a way as to end up with a certain number of faith points for the game. I once worked with a successful war-game designer who told me that he liked to give players as many "decisions under uncertainty" as possible to keep the game more interesting and provide some fog of war. I do agree that the current system does not scale well for larger battles.
I agree that Celestians and possibly the Canoness has lost some of what made them a good unit. However, I think that is compensated for by the fact that Repentia are now a unit worth considering and the Death Cult Assassins are a great deal for the points.
I would have liked the Immolators to keep their "fast" designation or at least given the flamers more range like the IG Hellhound. On the other hand I do like the Rhino costing the same as everyone else's Rhino.
Anyway, yes I wish that the Sisters would have received the Gray Knight treatment with a full new range and codex.
Failing that, I am generally happy with a minidex that cleans up the Sisters of Battle and brings them more in line
with the rest of the 5th edition armies. In general, I find that the overall effectiveness of my SOB army is about the same as it was before after reconfiguring and adding some new units to reflect the strengths of the new codex.