I see nothing wrong with enticing people to pre-order by including some free DLC for doing so. I think it's great actually. If I gave a damn about the free DLC, I would definitely pre-order, but I don't care enough right now, and I'll simply purchase the DLC down the road when I get around to playing Risen 2.
Oh I agree.. and I don't understand why some people are bitching about it. As I've said before, PB is simply rewarding the people who buy their game early, and I have no problem with that.
Now if this was a Day 1 DLC for $10, and there was no way to get it other than to purchase it outright, I might feel differently.