So fun question, does a mordor list with wraiths require fellbeasts to be competitive?

My list so far in inception!

Wraith-horse 2 might/fate.
Wraith-horse 2 might/fate.
Morannon orc captain.
Morannon orc captain.
Orc shaman.
Orc drummer.
38 morannon orcs- 18 shield, 18 spear, 2 banner, shield.
20 orc trackers.

Well, you have over 60 model, 20 bows and S4D6 infantry.i'd say you would be able to handle most things

Def5 hordes maybe a problem and not much F4+ could be a problem but I hope to mitigate those with the mission's objective or weapon strikes,

Is there anything I should be watching out for that'd cause me problems?

Lack of F4 might be an issue in some case, but you have good numbers so you can afford to loose some warriors
And Morannon with shield are D6, great !

Something that you should keep in mind is to take care of your leader, in scenarios needing one. Of course, there are other ways to gain VP, but it could be an issue against some armies, I suppose.

Who will be your leader ?

Leader-unknown yet.
Positives-
Morannon has combat ability, fury and D7!
Wraith has D8, horse, black dart and more fate!
Negatives-
Morannon-stuck in combat, accidents happen,
Wraith-sap will, combat drains his will!

Drummer and shaman are support heroes that aren't as survivable!

Which would you suggest?

.maybe you should switch one of them for the witchking, to have access to "your stuff is broken".
A wraith should be the general. Even a D7 morannon captain, with only F4, is vulnerable to heroes, and he cannot avoid close combat

I think in a lot of games, SBG, maybe especially people get a little overly concerned with what you need to have or take to be competitive. Fell beasts are really good, would they make your army better? Probably? But can you win games and have fun without them I am quite sure you can. Wraiths in general are good, Morannons are good. I saw go for it. The Wraiths on horses are super cool models!

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Cheers,

P

Witchking is one of my favourite looking models mounted and foot(with crown and face mask model)
That might be a good shout to add more will and the anti-wizard spell!

I personally believe you can make anything in games competitive if you play them right but due to seeing a abundance of feelbeast mounted wraiths I took it to be must have for most people but the horses will suit my force just fine.