B/W Midrangy Control

I think it has potential, but you'll need to tighten things up a bit. The Champion of the Parish doesn't fit well--you're not running enough humans to pump it up.  Most decks that run it also use token generation (e.g., Gather the Townsfolk) to make him big quickly.

Dutiful Thrull and Thrull Parasite may be replacement options, as the former offers Regeneration (for multiple chump blocks), and the latter allows you to leverage the Extort mechanic.

To add a few more thoughts...

- Finding a way to let High Priest of Penance survive a little damage could be really useful.  That or having an ability to ping him yourself in response to things.  I saw a build using Staff of Nin for this exact purpose.  Dude was able to block a creature with the priest, then ping it and take out the other attacker.  But I'm thinking things like Divine Favor or Holy Mantle... hell... even Mask of Avacyn.  None are ideal, but if you can turn him into a mini Phyrexian Obliterator you won't be complaining.
- Why not rock the other Exalted knights?  I see some Knight of Glory in the SB.  But why not Knight of Infamy?  Why SB rather than MB?  Who needs a chump blocker if your nighthawk is lifelinking for 5-6 a turn?
-  I would say to run more concrete, hard removal than Tragic Slip.  OR at least add some variety to it.  Ultimate Price in the MB?  Even Murder could be really useful.  Drop Tragic Slip to maybe 2-3x and go from there.
- I might be wrong, but Mutilate strikes me as a terrible option for you here.  If you have even three swamps in play, the only one of your creatures that will survive is Obzedat, Ghost Council.  Funny if you have Blood Artists - not so funny in your case.  Odds are you would end up screwing yourself up more than them in most cases.
- I'd also suggest trying the deck with Blind Obedience in the mainboard.  It can stop blockers, slow down any aggro deck, and all with the added benefit of an extort trigger.  Paired with some Thrull Parasites, even a top-decked one drop can be a big deal.
- Blood Crypts?  You can cast Reckoner with just white mana.  Unless you need the red for something else, you'd be better off drawing a plains than one of these.
- I don't know that I would run Cavern of Souls in this build.  Sure, it can be a mana fixer, but it can also get you stuck if you name the wrong creature type, as then it's just a colorless mana producer.  If you had more synergy with more humans or thrulls or spirits, I could see it working, but I can see where it'll trip you up a fair number of times given your scattered creature types.

I have something like it that I played for the first time today.  War Falcons actually worked great in the 1-drop slot...... I never thought there were that good, but this deck has plenty of knights and soldiers.

turn 1 war falcon -> turn 2 knight of infamy/glory and swing with flying 3/2.  not bad.  I finished with either Obzedat or Blood Baron of Vizkopa.  Here it is: http://deckbox.org/sets/391903

I like this way better than my previous straight Orzhov.  I need to get some of those Angels you're using.