Is it worth to buy the Assassin's Creed II when I've already finished the regular one?

The short answer is - I doubt it would be worth it, unless this is one of your favorite games. How much of an Assasin's Creed nut are you? :D If you enjoyed the game greatly and would enjoy playing through the core game again in addition to the additional content it will be worth buying, however it may be worthwhile to give it a long time to come out and drop in price.

I was unable to see if you would have to get the trophies again, but if you are planning on a robust replay I doubt that would be much of an issue.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.