How to farm orens

CD Project has commented on the save imports but nothing is confirmed yet. Anyway, here are some vague points:

• Some quest- and major decisions will be carried over according to your past choices
• Characters might react differently to Geralt depending on you completed TW1 (1)
• Importing some of the weapons and armor (2)
• It will impact the story, though not in a way that it changes it completely (2)
• It will not import your money from TW1 (2)

From what I've seen and found from other discussions:

You get less or more experience depending on the level difference(which makes the game more challenging).

Experience gain is limited by mob type or area(to prevent extreme farming...or as protection, because it's possible in games that due to some bug you get imbalanced experience over and over).

Max level by chapters, I'm not sure abut this, but when you go to complete quest and gain no experience it could be this(makes the game challenging and protects from farming).

Level 35 max level in game(useful for planning skills).

And lastly the plain old bugs that occur in every RPG that tries to give you more freedom.