Developing a Necromancer hero.

Why are melee units better than archers? If you don't take archers, the only archer stack you'll have is liches, and they're large and easily blocked. But even if skeletons deal little damage, they can play a very good role in a direct attack.

I think Vadimh's point was that in a battle against another player, the presence or absence of an archer stack isn't that important; what matters more is the attack power of the unit. And Necromancers always have a lot of skeletons, so they can be used alongside zombies as cannon fodder.
However, archers are needed against neutral creatures. It's not that you can't do without them, but it's better to have them...