The game isn't just a rehash of Heroes III, either. There are new features, such as Hero Trails, which will make heroes easier to track, a lot of new skills (which are still being worked on at the moment), and the fact that you only get one hero per faction, but as you play a scenario you can customize him as you see fit.
The game will ship with six campaigns and 30 individual missions, as well as multiplayer support for LAN, Internet, and hot-seat. While only two of the factions have been announced (Inferno and Haven, aka Holy Knight) Nival says that three of the other factions will not surprise anyone but the final one should surprise a lot of people. (We prodded and poked and tried everything we could but they wouldn't say what it was.)
Heroes V was definitely one of the bright spots of the show for us, and we'll certainly keep an eye on its development. Long-time fans of the series are finally going to get what they have asked for, and hopefully it all comes together as planned because turn-based strategy fans don't have a lot to choose from these days.