Only a few of your points I'd like to expand on...
2. It would be cool to have more complex combat system (blocking with your shield, Demon's Souls anyone?).
100% agree. The combat in this game is throwing a horde of enemies at the player and it comes down to potion chugging, until you get so overpowered that you take very little damage and instead put up with constant stuns. I'd much rather have smaller enemy groups (large groups of 5 - 6 enemies being a rare occurence) with deeper combat mechanics.
5. When you see an empty barrel/chest/crate or you have just pillaged it and took everything, I think that you should no longer see/be able to click on it. This would ease exploring I think. It's kind of boring seeing many "empty barrel/chest/crate" messages.
Once again, I agree. If it's empty to begin with, there's no reason for it to be targettable. Once I've looted something completely, it should no longer be targettable.
6. Although I'm happy with size of the world in this game, I would really love to see trully open landmass in next game (Oblivion etc.).
This is where I have to disagree. I was really turned off by Oblivion because it was such a vast world that it seemed like every other aspect of the game suffered because of it. Combat was weak, loot was weak, leveling was nigh on broken, dialogue was bad, the story was weak, the game was plagued with bugs, and it felt devoid of soul. If it weren't for mods, I never would have completed that game, and it took a heck of a lot of modding for it to feel like a proper game to me - and I still didn't spend more than 20 hours on it.
Divinity 2 has a decent mix of linear and open-world, (mostly) great voice acting, and an absolutely outstanding soundtrack. I think they need to fine tune their current system and they'll have a masterpiece on their hands.
