After playing the game for a little (around 4 hours). Here are some suggestuions:
Most important for me:
-Shared XP between the 2 Characters
Currently only Quest XP is shared, all other XP comes from who gets the last kill. My Mage with his powerfull AoE spells is doing so much more damage than my other character that he gets more kills and more XP. I would rather see XP shared on both characters equally, or maybe if you really don't want this: XP based on how much damage you did to the Enemy.
While we are at sharing:
-Shared Gold when shopping with vendors.
It is fine that each character has his own Inventory, but they really should share the gold so shopping is easier. And maybe add a Button to change the character with a open shop window so you can sell/buy items with both characters at the same time.
And here a minor something:
-Pausing the game with a Button (Baldur's Gate Style)
I could add some class/talent balancing things, but im sure balancing is in no way done so i'll leave that out for now.