They should have named Chapter 3 + Epilogue just Epilogue. Though, I understand that then people would be complaining about game is too short. :)
The game has actually 3 chapters but it's going like this: chapter 1, chapter 2a and chapter 2b. And you ought to play both sides because chapter 2a and 2b are so different that it's like playing another game.
I also was disappointed in chapter 3 on the first walkthrough when I was salivating to participate in the intrigues between different sides with sabotage, persuasion and diplomacy quests... and then boom... the game ends. :(