The only problem I have with the 1k section is the lack of scoring units, 2 small units of Horrors aren't exactly able to take a lot of punishment either. I'd look into replacing one of the units with a group of Plague bearers (when it comes to holding objectives, these guys are the bee knee's).
1.5k One Soul Grinder on its own isn't that great in my opinion, I definitely think they should be taken in pairs, threes or not at all. Perhaps sub one of the Bloodletter units for a second Soul Grinder? Though this again leaves you a bit low on the old troop count.
2k I really think the hounds and Karanak are a bad idea here, you could replace this unit with an extra squad of troops. Perhaps not add the icon to the Bloodletters, I think deepstriking them onto the unit of Bloodcrushers and deploy behind them is a good way to keep the 'letters alive; they will get cover from the Crushers and your opponent will have a rather imposing unit of monstrous brass knights in front of him that should draw fire