The biggest complaint I had about Divinity 2's inventory system was that most of your inventory space tended to be composed of a TON of Ores, Gems, Plants and potions in Broken Valley, and a lot of the time finding formulas to use them on was random luck, and there was no way to store them for later. (The increased storage space skill never seemed like a worthwhile use of skill points compared to killing enemies faster.) Someone in Broken Valley who just sold formulas might have helped with that.