Dark Marshall- horse
6 Morannon Orcs - shields
6 Morannon Orcs - spears

Shagrat, Captain of Cirith Ungol - shield
6 Black Numenorians
6 Orcs - spear

Mordor Orc Shaman
6 Orcs - shield
6 Orcs - spear

That's 498. Each warband can act independently if I get shafted on deployment. Ideally the two all Orc warbands will stick together for Fury purposes. The other warband can act independently with higher F and a beefy hero. No shooting but that seems to be the norm for evil.

I like having 3 full warbands. But my big question would be this: is it worth it to drop 3 Morannons to turn the 3rd warband into Morannons instead of regular orcs?

I like it, although personally the best wraith is The Dwimmerlaik. Also, mount your Shaman Bro. If you fluff your fury you get a cavalry model with 2 wounds (and maybe 1 might), and he is easier to get away from big scary enemies.

I'd swap the Morannons with shields from warband 1 with the Black Númenóreans in warband 2 - the latter are better when near the Dark Marshal, when enemies have a -1 penalty to charge them.

And spend the two points spare on some extra shields.

Interesting. My thought was that the F3 orcs would benefit more from the banner than the F4 Numenoreans.