This isn't a new idea, but I really think this game would benefit from it. I'm talking about adding an option to make the game harder, something like an insanity (or a Divinity) mode. So you would have easy < normal < hard < insanity.
To argue about the need of this new difficulty, I'll talk about my experience with the game, which of course I really enjoyed, thus I'm here trying to make it better.
I'm a veteran RPG player, so I began the game on hard, cause I know the hardest mode usually is the most fun.
In the early game I surely died a few a times, cause I was still learning what everything did, experimenting with combos and whatever I could find or think of.
I saw the trait "Lone Wolf" early on and thought that would add even more difficulty and fun to the game, so I decided to play on hard with only 2 characters. I also learned about the perception ability to find secrets and decided to invest in it as a "main" stat.
By the time I built the Source Hunters, I was with a glass cannon mage that could control the four elements and combo by herself, and a tankier all-in melee.
Now, on hard, with both lone wolves and 13 perception on my mage, I never even come close to dying, the game clearly got too easy without me even trying to do the best possible combat-oriented party.
The new mode would be completely optional, it would appease a more "hardcore" audience, while newer players could just ignore it, also, this would be nice as some kind of small NG+ addition, I would replay the entire game if I had a significantly harder combat option.