So, I found a shop, and there is a great discount. 50% for boxes, 60% for blisters.
I asked a list from them, so I could decide what I want. The problem is, I dont want to buy unnecessary units.
My question is, what do you think, shoud I buy the follow units?:

Mordor
-Troll with drummer - I already have 2 trolls, and Im thinking about a third one, a drummer troll. Is it useful in WOTR?
-Undying, the nazgul
-morgul knights- the fact is I already have one box of morgul kniths, but as I heard they are very strong, and effective. Is a 6 companies of morgul kniths good for war?

Harad
-Khandis riders with captain (I dont have any infantiry for my fallen realms army, are they good? Does anyone have any of them?)
-watchers of karna or serpent guards, or none of them? Im thinking of a special harad unit. Im not sure.

Hi Bastion. I really like your army as it is but expand to look cooler. Troll Drummers are only useful IMO if you have at least 4 other trolls to make irt worthwhile. The Undying is the weakest of the eight cheap Ringwraiths but (as an Epic Hero) is much better value than your beloved MoS so is worth it still. Morgul Knights are awesome, take as many as you can, but keep them in formations of 3 (their maximum size is 4 anyway which is just plain stupid). Khandish Horsemen aren't worth it, if you had the infantry they would be ok though, Watchers of Karna with bows are ok, but Serpent Guards cost weigh too much (Serpent Riders with a hornblower are good thouh).

_________________
"I am the Flying Spagetti Monster. Thou shall have no other monsters before me"
-FSM.

Why do you think that the khanish warriors arent good for cavlary, just for infantiry?

What does it mean IMO?

IMO means in my opinion.

I mean Khandish Cavalry aren't worth it, I used them once but mounted archers are always a waste of pts. Khandish Warriors on foot are useful though, especially a 6 company block with two-handers (and the archers purely on cheapness).

_________________
"I am the Flying Spagetti Monster. Thou shall have no other monsters before me"
-FSM.

I see, that the Ringwraiths has the spirit grasp spec rule. How does it work? Their courage is 5. If you put them in a shielded morannon orc team, will he reduce their defence, or not?

No, firstly Spirit Grasp doesn't reduce anyone's defence, especially not one of your own formations it just means you strike at Courage rather than defence. Secondly, the Spirit Grasp Rule is for fluff only, it is useless as it does not ever transfer to his company/formation.

_________________
"I am the Flying Spagetti Monster. Thou shall have no other monsters before me"
-FSM.