2. If a loot container is empty just say so on the tooltip for that container. It's busy bee work making players open every loot container to see if it has anything inside of it. I've seen other games do it this way and it allows the pace of the game to be picked up a bit which DOS actually needs IMHO at this point.
If you open a container and there is nothing inside, then the container description will tell you afterwards that the container is empty.
As far as I know, there are two reasons why the container description doesn't tell you at the beginning whether it is empty or not:
1) In most containers the loot is random and the loot generation occurs at the moment when you click on the container.
2) I think that it is also in line with Larian's idea of exploration that you have to search for loot very carefully and do not see at the first glance where the loot is located.