Is diplomacy necessary?

Dmitry_A_S, we're talking about Heroes of Might and Magic, specifically about creatures, like an upgraded Archangel. That's why it was written that way – it was just an expression. And the idea that you can't recruit more creatures than you can buy in your own Castles is a misconception. You can recruit any army you want, to suit your taste. And if we're talking about morale, then someone who uses diplomacy should be aware of this, and therefore should take care of a secondary skill like leadership.

Well, if you have 7 creatures from different Castles, and even undead, then even expert leadership won't help. Moreover, such an army cannot be replenished – unless you capture another Castle. And creatures of level 6-7 almost never join. Also, neutral creatures often require astronomical sums to join. The question is, by the time you develop expert diplomacy and find creatures willing to join, enough time will have passed for the computer to develop well and, if not destroy you, then at least severely weaken your mixed army. Of course, on the "Pawn" (easy) difficulty level, every other creature will join without diplomacy. But I prefer to play on "Rook" (hard).