The most difficult alternative

Bards significantly reduce speed. Ghosts are excellent, but they come from necromancy... although the more, the better. Thunderbirds are good, but building them is very expensive. Useless castle and stronghold... Expensive, but nice. :) WD or Phoenixes? It's very difficult here. Portal is always good... Although Phoenixes are preferable in battle against Dungeon. :) WD easily defeats the rest. However, with a specific tactic, the value of WD is lost. Djinn... but it's better to use cockroaches for illusions. Nagas are a beast in the hands of a skilled mage, but they need to be developed, and Djinn will allow this to be done without problems. There is no definitive choice, there are only different tactics. :)