Sacred Haven of Debauchery

Why is a sixth installment needed? Couldn't they have waited for the expansions to come out, or whatever they're planning to do, so they could add everything at once?

And yes.

Choose the part of Heroes that you would like to progress through based on its ranking system.
Heroes of Might and Magic 3 [Heroes 3] Heroes of Might and Magic 5 [Heroes 5]

Apparently, because they didn't include images, and there's no point in including them since they're disabled. That's why there's no point in writing about the other installments, although there might have been problems with the fourth one).