I think it's pretty cool. i'm brewing something similar to this, BG Whip but i keep finding things i don't need and that are better; resulting in bad trades. XD
But that aside, desecration demon. Take out the Deathrites and slam in a mana dork it's just better cause he doesn't do anything on turn one and swings for 1 on turn to. I much rather have the new B: 2/1 black dude if you want damage. Pairs well with boon on bestow.
I love Desecration Demon and I am glad I've been sitting on a playset because its price is rising fast! :)
As for Deathrite Shaman I don't really ever plan on attacking with him. The idea behind this deck is to drop an early threat and then disrupt my opponent with counters removal and Thoughtseize while the little dude I dropped early beats face. Deathrite fulfills this role really well (exiling my counters = 2 unblockable damage every turn, I can even gain the Thoughtseize life back!).
If deathrite does not play test well then I will def replace him for mana dorks. A turn 3 Desecration Demon seems pretty good.