There are different types of templates, and map sizes vary.
Often, there are templates for large maps where a game can last for two months.
And often, people play templates with just one castle.
On custom maps, they almost always create either one native castle or several castles of the same faction.
As for recruiting neutral creatures, it is usually prohibited.
So, the converter is not usually used in practice.
In a long game, Necropolis is not the strongest... I don't know why people think they are the strongest...
Especially with several native castles, Necropolis is completely out of the game...