What skills should Necromancers take when facing Orcs on a very large map?

Which specific comments led you to say that? And... are you saying that you have a lot of experience playing online, considering that all you hear here are "funny things"?

For example, the suggestion that Necromancers should upgrade Cursed Land (it deals 12 damage to Orcs), so why upgrade it? Or that Orcs should upgrade Anti-Darkness (they can defeat Necromancers without it, and if they do upgrade it, they'll just waste experience and an extra skill slot). Or upgrading Attack, Defense, and Luck against Orcs (what's the point of that?). Or that a Necromancer has an 80% chance of winning, which is only true if they really try and the opponent plays very poorly! So, that's where these conclusions come from.