Community manager Acheval started a question thread in the Dark Messiah official forum for fans who have questions about the game. Game director Raphael Colantonio provided some answers halfway through the second page of the thread, so I'll post a summary here:

• AI: "AI adjusts it's strategy according to your tactic, your equiped weapon, etc... But there is no dynamic AI difficulty system (...)"
  
• AGEIA Processor Required?: "no"
  
• Melee Combat: "The philosophy relies on lots of context based actions, rythm control and AI state management. This provides a lot of variety, it provides tactic and action at the same time, and most of all, you can use the environement a lot as part of your tools to kill enemies. For example kicking NPCs into the fire, off the ledges, into barels, etc.. Grabbing heavy objects and throwing them at NPCs..."
  
• Micromanagement: "the RPG side of the game is very intuitive and accessible: there is an open persistant inventory where you can store all your items and goodies, and there is a skill screen where you upgrade your character as you progress through the game."
  
• Multiplayer co-op: "no, good idea though"
  
• Map Editor: "probably so"

There are more answers at the Round Table. The official forum is still fairly quiet two months before the release of the game, but I expect Ubisoft to generate a lot of hype during the next couple of weeks.