Since I don't know your list, I can't say much. All I can say is that the deck gets a lot faster with ritual, and I say that from my testing. Maybe you should try it out... I've tryed ritual-less versions and I always play at least 3. Ritual helps in lots of situations where you want to delay their game T1, and yet do some other stuff. Also, it gets you crucible t1 sometimes, making smallpox and pox a lot more useful. In the late game it's also quite common for it to help tombstalker #2 to enter. For those reasons I think dark ritual is a house. But again, that's just me...
I think the most important point on this topic is to find a way to do some serious testing together, to try to find a "raw" list for players that actually could run it on tourneys... then the deck may reach DTW. I can do some aggro like Eva Green and gobbos, and some aggro-control like thresh and CB. Not a good combo player, besides painter that is rather easy to play. I can run SI w/ Ad Nauseam, but can't guarantee the results before some testing...
EDIT: Answering Mok.
Nice, some combo test would be great... I have not a very good idea on how this deck goes against TES... dunno a good TES player to test... Time to test is always an issue... we will have to exchange MSN's in order to meet each other... that may be done by PM if you all agree.
I think we should start by testing a list with greater common sense, even if it means (for me) to let few cards out (like tops and rituals)...
Ideas are welcome there.
My personal one would be:
// Lands
3 Wasteland
2 Tomb of Urami
14 Swamp
4 Mishra's Factory
// Creatures
3 Tombstalker
2 Nether Spirit
// Spells
3 Crucible of Worlds
4 Hymn to Tourach
3 Powder Keg
4 Sinkhole
2 Pox
4 Smallpox
4 Innocent Blood
4 Duress
4 Dark Ritual
// Sideboard
SB: 1 Powder Keg
SB: 4 Tormod's Crypt
SB: 4 Engineered Plague
SB: 3 Infest
SB: (missing the card here)
Thoughts?
EDIT: Sorry about the double posts =/

