UD&ORC

I don't understand why orcs need ranged attacks. A stack of Pikemen is only good for clearing neutral creatures, but they'll be the first to be blocked or spell-controlled in a battle against a Necromancer.

If you're playing as Haghesh, Pikemen move more often (and if you speed them up and push them forward...), they can attack at least twice before the Necromancer's hero casts a spell. If you split them into two groups..., it's not very effective in a long game (when there are many Cyclops).
The ultimate ability (I don't remember the name) deals damage based on the number (not the quality) of the army, which can be useful in battle (this also applies to Pikemen - you can recruit quite a few of them).
The main thing to remember is that Necromancers almost always play defensively, while this is not suitable for Orcs.