Here is another minor thing about UI you might consider... Dropping things is now done only by dragging item out of inventory to the ground, which sometimes can be a bit inconvenient. Classic situation (which I already found myself in more then couple of times ) - you are killing Roshan with your mates and you need to drop item so you have space for Aegis, you also don't want to move away, so you need to drag the item aprox. to middle of your screen, which is full of heroes, Roshan and if you release your item on something you have to do it again.
My suggestion regarding this is to add an option to the items right-click menu to drop the item. This way it would be easy to drop the item when you need to do it, also since this menu is rarely used, it shouldn't cause any problems like dropping your whole inventory on accident.
One more thing - you can't drop items from your stash when you are dead (you can click the option but game tells you you are dead). I'm not sure I remember this, but I think in dota 1 you were able to do so, so is this a bug or a feature?