Here's an attempt at making a 500 mordor list, but a good one that can take most good forces at this point value....
tell me what you think...

Minas Morgul
Black Numenorean Marshal-shield-65p
Barad- dur
orc shaman-50p
12 Morannon orcs-shields-96p
6 morannon orcs-spear+shield-54p
5 morannon orcs-spears-40p
4 Black Guard of barad-dur-48p
6 warg riders-72p
15 orc trackers-75p

Exactly 500 points
50 models
15 bows
3 might

a good spearwall of morannons, 15 orc trackers that can volley shoot or shoot directly, 6 warg riders for speed to take objectives or to act as a arrow-shields, and 4 black guard to break enemies that have D7 or heroes. The shaman can cast fury to give the orcs a fate roll, and make them fearless, and the BN marshal is a solid captain with good all round stats.

How does it look?

a very nice list
I would swap the black num marshal for shagrat with a shield an take more black guard, but that's all.

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"make me lunch... worthy of Mordor"

A nice, solid list. I'd prefer to have more Black Guard or none at all, as just four doesn't seem enough to do anything. Also, have you considered using Morannon Orcs for the first line of your shield wall, and then regular Mordor Orcs for spears? That could save a few points.

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"There are few left in Middle Earth like Aragorn, son of Arathorn." - Gandalf, Many Meetings

yes I could drop morannon spears for mordor orcs w/ spears saving points, but i'm already at 50 models, i really can't upgrade anything or buy more men, and morannons make a strong phalanx frontline and second line....

Most peole would recommend throwin a wraith in there, but it's up to you.

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

a nazgul is a good choice, I could take a black guard captain as a hero choice to lead the mordor contingent, but I also like the combo of a BN marshal with high stats for high leadership, and an orc shaman with fury to boost the rest

The special rule for the black guard if a nazgul is around makes them have a very high courage. Also a generic wraith has a higher courage (6) than the named ones.

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richmondwarmancers we play Lord of The Rings, Battlefleet Gothic, Infinity, some board games, and really whatever tickles our fancy..

Only the SL has courage 5, all the others have 6.

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"War does not determine who is right, only who is left."
- Bertrand Russel