It's immediately clear that the person lacks experience in online gaming. Because evaluating a Castle based on its fastest unit is a thankless task. Back in those distant times, when I was building a Stronghold and playing hot-seat with a friend, he said this to me: "I only play as those who have the first turn in Utopias." Now I can appreciate how absurd that sounds. The same Stronghold and Fortress simply crush Utopias in the early stages. I won't even mention Necropolis, where dragons are never built. Another nuance is that green and red dragons will appear at some unknown time, while bears and hydras can be built in the first week (and with the Castle) and can start providing real benefits from the second week. There are situations where the first turn is a decisive factor for victory, due to the first cast (antimagic on your stack or explosion). Well, in this case, you just have to figure something out. But there aren't many such situations. In my opinion, the table is missing: silver pegasi, master djinns, wyvern monarchs, red cats, sultans, and some un-nerfed creatures.

In general, it seems to me that the game developers have messed something up with the Stronghold and Fortress: Rukh is the most suitable unit for level 7, the "bears" could have been reduced and made level 5, and wyverns and hydras could also have been swapped.

To understand how strong these Castles are, you need to play online.