I personally wouldnt go with Lord of Change, far too expensive, take 2 heralds of tzeentch on chariots instead if you want a ranged character.
plague bearers- good. Use for taking objectives, self explantory.
This list really needs more staying power, and units that pack a harder punch. Incidentally, bloodcrushers have both. You could probably drop one of the units of BL and take something else, maybe fiends?
Screamers are also alright, 6 is fine because theyll have a hard time hitting moving vehicles with 1 attack each. Theyre also a pretty uncommon choice so its nice to see people using them.
Thats all for now.