To quote Swen from his own blog: http://www.lar.net/2013/09/18/an-important-lesson/

Originally Posted by "Swen Vincke"
So yes, I discovered a few interesting lessons.

The most important one for me was that in the future I'll try to only commit to a release date when the game is actually done. Not if it's 85% done or even 95% done, but only when really, it's done. As in, ready to be released.

Divinity Original Sin has already failed to learn from this lesson.

Quests and Dialogue

Many dialogue options that players expect are missing, and completing certain parts of a quest out of order breaks the quest or makes parts of the dialogue nonsensical.

Just look at the problems facing quests such as the Murder Mystery and Headless Nick. People do things out of order, want to ask certain questions, etc., and these are problems that can only be resolved through testing by a fairly large number of users.

Considering 80% of the game content is not yet released, I can't imagine the quests in the next major town being anything other than an utter mess of unsatisfying dialogue options and NPCs not reacting properly when you did something before you were supposed to. It is not surprising that Larian was unable to code quests to accommodate the crazy things we did in Cyseal (and most of those have been patched), so how can we expect anything different for the rest of the game?

Balance

This is not intended as a comment on the current balance or difficulty of the game. There are other threads for that. However, I think it is undeniable that the balance work is still very much in its infancy. In this last patch, we saw the skill system completely reworked, massive changed to enemies and their abilities, and huge improvements to the enemy AI.

This may be stating the obvious, but even small flaws in a game's balance can have a severe impact on how it is perceived by the players.

If even one or two abilities are too powerful, then players who happen to use them will find the combat boring and tedious because it is too easy. If there are strategies and tactics that make the game simpler, then players who wish to play the game multiple times will fall into the same category, simply because they learned too much about it. Anyone that is struggling and looks up a player-made guide to figure out how to stop dying will quickly join them.

Once again, it is unreasonable to expect Larian to crunch numbers and spit out a well-balanced game. Since most of the content is not in the game, in order to test it for balance Larian would need to play through the game with several playstyles (doing all quests, skipping quests, etc.), with various types of characters, completing the areas in different orders (such as going north of town before west), make any necessary balance changes, and then repeat the process several times.

The game will be released in less than a month.

I hate to be so negative, but how exactly do we expect these things to work in the unreleased content?