I prefer Poly K, he can clear the way for himself to hit face. Deadbridge doesnt do anything on the board and 6mana for a buff whilst free is a lot to ask for.
If your environment is very condensed, I would lean heavly towards night's whisper, since you only have so many windows to cast your sorcery speed draw spell. In general though, night's whisper does a better job smoothing out draws where you have 2 lands and need to find the third land. However, read the bones is better in situations where you are mana flooded.
I guess I would lean towards night's whisper in a vacuum, but I like both cards.
I think we talked about the whole Black divination thing earlier, the conclusion I came to was that Night's Whisper was the coolest because costing 2 > costing 3 by a wider margin than scry 2 > nothing, and 1B > BB by a wider margin than target > no target.
FWIW the power level is obviously there for both cards.
I meant Butcher Ghoul. I know the upside is a little higher... well, it depends on whether you care about +1/+1 counters I suppose. Manifest misses at 2/3rds of the time, and the manifested 2/2 is no longer a Zombie for cards that care about that.
Sultai Emissary totally plays better with CML's brainstorm package, FWIW. Which naturally pushes U/B into being a TINY bit more interesting as far as creature strategies go.