Tactics against Necromancers.

It depends. Sometimes diplomacy yields much more. And that's why it's important to use it to the fullest against Necropolis. By the way, it also prevents them from creating skeletons.

Exactly - "sometimes."

You know, personally, I find a steady increase in troops (necromancy) more effective than a random one - lucky/unlucky (diplomacy). The first is always available, the second is much less frequent, although it can be very significant, but you can't plan for it and rely on it. And therefore - it loses to the first. This is about tactics...