@b0rsuk: Your first two points are ones that I - and the folks who worked on DK2 that I have spoken to - agree with...
1. To me personally, MP - or more specifically, the sandbox-like gameplay - is most important. Every other mode is based around this sandbox, so we need to get it
right before even moving on to doing a campaign, etc. The problem you are describing is what we call 'Defender Advantage' and you are right in saying that it broke MP in DK2. Some (but by no means all) of the things we are doing to fix this:
- Blood (an energy-like resource) has replaced Mana is designed around limiting how much you can influence the physical world in a short space of time, meaning that your ability to abuse the defender advantage is severely diminished
- Later on in the game, there are going to be multiple ways of getting through fortified walls
- There are many, many more incentives to actually go out and explore and control parts of the map, making not-turtling a viable option