My problem with cutting revoker and also with 4 serenity (which i was thinking about a bit) is that walking ballista is SO GOOD against us. Now maybe serenity is good enough that i don't mind if they draw ballista after I wipe their board and my revoker/stony.
As for prelate, I agree that it is a bit slow, but I think if we can slow down the game with our other stuff, it locks out the game which is quite pleasant. Interestingly I sided it in against everything i played that wasn't shops. Naming 2 against oath seems VERY good. It wouldn't come in against Dredge probably, but overall I was happy with it as a one-of.
I have actually played Devout Witness in the past and I was considering a different spellshaper actually in the form of Hammer Mage. I will test out serenity, and I also had a crazy thought involving ancient tombs and Settle the Wreckage that might be crazy.
I really liked this list against everything that wasn't shops. My only other loss on the day was a close match against jerry yang's paradoxical oath which turned 1'd me in game 3, I want to chalk that up to just getting vintaged. Our games were super interesting. In game 1 if I had a chant in hand I would have beat him when he oath'd his whole deck and had to memory's journey to be able to win with will, had I had the chant (or consultation) I could have blown him out in response to will with 0 cards in library.
I definitely agree with you on Revoker. It's one of those few coveted cards that are good in a lot of matchups, and I'm not really happy to be cutting it from my lists, but the disapperance of Jace from the metagame (more or less) makes it a little better.
Yeah, Prelate is very good vs Oath and (and Jeskai and exceptional against Landstill). Glad to see someone else play it!
Hammer Mage does seem interesting. In fact, if you really want to beat Shops, adding red is probably the way to go. I've had the most succes against Shops playing Red/White with Ancient Tombs and By Forces and Meltdowns.