Thank you very much for the advice. From advice I've gotten from other forums as well on this deck, they said it is difficult to make it really competitive and recommended a mono black control build similar to this by Jeff Kruger:
4 Mishra's Factory
1 Maze of Ith
4 Wasteland
1 Strip Mine
1 Urborg, Tomb of Yawgmoth
5 Swamp
...
Have you tested this deck? I have to admit I haven't, but I played a lot of Suicide Black, back in the day when it was an answer to mono blue.
It seems to me your mana-base cannot support your spells. The amount of black producers seems way off. I used at least 15 swamps, but 16 or 17 usually felt better, then come 5 strips which you desparately need for disruption, and your total base is 22 lands.
If you want an excellent primer on the subject of Suicide Black you can read the one by Legend. It is dated by now, but the basic points are still the same and still very valid today.
http://www.themanadrain.com/index.php?topic=11797.msg222583#msg222583As a quick update:
Since the days of Legend, Discard has changed from being a threat to being an enabler. I believe Hymn to Tourach is no longer playable in Type 1 (Ichorid, Goblin Welder, Y Will etc)
So it should definately be replaced by Thoughtseize.
A second point that is not adressed in the primer (I believe) but which came to me during my testing, back in the day is:
Do I need Dark Ritual?
If you are not going for storm, and you are just running one Yawgmoth's Will, without any tutors...
Do the Dark Rituals actually help you?
I'm not saying they are useless. But I do say that they require significant thought and a deck design that is built around them.