Yesterday, I played with a friend in a 3-player game. I got Rylander (Roland) randomly. In the first week, I approached the passage between our castles, and there were 50 Dryads. In the second week, they all joined me for money.
He was very surprised :) Especially considering that I only had elves and dwarves on my territory. Can you imagine what I collected there?;)
And he was playing as a fair Krag. It was the easiest victory I've ever had in Heroes.
As for specializing in mysticism, you're wrong. At level 10, these guys regenerate 10 mana per turn. And that's not the limit. In Heroes 5, IMO, it's a very useful specialization.