Norwegian site Gamer.no have published a Q&A with producer Erwan le Breton. It is a net-meeting kind of Q&A, with the various readers posting their questions and Erwan typing in his replies. The start of the article (the introduction) is in Norwegian, but the actual Q&A is in English, so just scroll down the page to find it. Here are a couple of tidbits:

Q:Why did you decide to remove town view from homm5?
A:The town view has not been removed - it is still there. But we agree it is not as nice and rewarding as in the former Heroes. Improving these town views is on top of our post-launch support priority list.

Q:How many factions can we play on release, and will you add more later on?
A:5 factions are present in H6, out of 9 that are present in the world of Ashan. So there is ample room for additional factions in possible extensions.

Q:What would you say was THE toughest choice/compromise for you during the development?
A:The toughest choice was the revised skill system. It was discussed at length with the VIP fans from our private forum, and our first proposal was (justly) discarded in favour of the current system.

Q:Why where so many resources removed? Less resources equals less fun. One of the fun part of the Heroes of Might and Magic games is to find the right resource.
A:The 4 rare resources have been combined into a single one, called “Dragon Blood Crystals”. Its existence is linked with the history of Ashan. We have three main reasons for this change:

• This brings more strategy to the game. At first, you could think this is the contrary but on former Heroes, each faction had his specific resources to look after and so did not care much about the other guy and his mines. Now that every faction is looking for the same resource, mines possession will be much more strategic as you’ll also prevent the other to take this crucial resource.
  
• Games with a lot of resources are not strategy games but management games. If you look at Starcraft 2, they have 2 resources. Games such as Settlers VII (7 resources) or Civilization V (32 resources!!) focus more on management. In the former Heroes games, you would often spend a lot of time collecting rare resources that were useless to you just to convert them in the marketplace. This kind of micromanagement was not really the funniest part of playing M&M Heroes...
  
• It is much easier for map makers. You don’t need to think too much about which resources to place on the map depending on which factions are present.
  
  Read the whole thing here.