bundle of Divinity II - Ego Draconis and Divinity II - Flames of Vengeance, but The Dragon Knight Saga really is much more than that. A lot of us like to think of it as the game that Divinity II - Ego Draconis should have been, and if you played any of the previous Divinity II games, you’ll discover that many changes were made not only to the game engine but also to the game content.

These changes reflect the insights we’ve gained from seeing people play the previous Divinity games, and we think all those changes combined, together with all the extra content, make the entire Divinity II experience a lot more fun. Returning players will find that where we thought the game flow was broken, entire areas have been modified, and that many in-game actions that could at times be frustrating, have now been made much more accessible. There have also been many performance improvements and you should immediately see that the graphical quality has been increased.

–Swen Vincke, Game Manual

b) Most anti-dragon zones (the red auras) have been removed
c) In a lot of places enemy placement has been modified, especially in the latter parts of the game (e.g. Oroboras fjords)
d) Loot balancing has been radically changed
e) Difficulty spikes have been addressed
f) Major graphical overhaul
g) A variety of mechanic changes should make combat feel better (e.g. no homing missiles, level difference not that important anymore when dealing with enemies)
h) A whole bunch of usability changes (which are also present in FOV)

–Lar_q, Larian Forums