(Hero - Rogue) in Heroes 4

I can hardly imagine an online game where you have time to hire up to eight heroes without harming the rest of your economy... I think the development there will last only a few days.

Why do you say "hardly"? Do you think you absolutely need 8 heroes to reach the enemy's Fortress? You should have participated in Kanighem's tournament for Heroes of Might and Magic I; when a description is made, try to read it. You'll be surprised how many heroes were bought there in one turn!