Which units would you replace in the Sylvan castle?

Personally, I don't like Ents, not even since Heroes of Might and Magic III. They are certainly powerful in Heroes of Might and Magic V (unlike in Heroes of Might and Magic III), no doubt about that. But their appearance... And they are slow. When playing as Elves, I only use them to defend my castle, as I prefer an attacking strategy, and Ents, in my opinion, are purely a defensive unit. I've been thinking about what to replace them with (so that they would be comparable in strength to the 6th-tier units and fit the spirit of the castle), but I haven't come up with anything. So, I guess I should probably keep them (specifically for defending castles or for a decisive battle). All the other units, in my opinion, are already in their right place.