RTF is a global modification that replaces all towns in the game.

So, you mainly didn't like it because of the two types of steel? Well, you could rename, for example, Dusk Steel to something like Obsidian.

This is needed to make the requirements for buildings more logical. Sometimes it's unclear why certain resources are needed in a particular building. For example, why are crystals needed to upgrade a building where Knights (forgot the name) are recruited? But something like Dragon Steel could be used to reinforce the building, etc.

I didn't pay much attention to the appearance, so I can't comment on that. If you change the names, it will create confusion due to the double changes (the appearance was taken from 7, but the names were pulled out of thin air).

Regarding the logic, in the case of the Knights, it's not just an upgrade, but an upgrade that switches to a magical branch (Paladin), hence the requirement for crystals. Rare resources like mercury, sulfur, crystals, and gems can find logical applications if used with creatures or buildings that are related to magic.