Just my two cents:
If the number of containers in an area is large enough, two players will end up with approximately the same loot after clearing this area due to the mathematical law of large numbers. So, say, there are 1000 containers in Cyseal and the probability of finding a healing potion is 1/4, a dagger 1/4 and a lockpick 1/2. Then player 1 will end up with 244 healing potions, 267 daggers and 489 lockpicks. Player 2 will have 269 healing potions, 507 lockpicks and 224 daggers. So, balancing is pretty easy for large number of containers because of the underlying probability principles.
As Tanist has said, save scumming is an "outside" game influence. When balancing a game, this should not be taken into account.
How many containers and creates are in Cyseal? And how many items in the loot table? Let's assume there are around 1000 containers and 100 items (with a constant probability distribution function). If you want to receive a specific item from each container, you have to load the game 100 times on average to get it. Assuming you need 1 minute to load the game, then you'll spend 100 000 minutes or 30 hours with just saving and loading to optimize your character. If someone would like to spend so much time - well it's up to them! (Even you want to get a specific item, say a healing potion, from a certain chest then you still have to invest more than an hour to get this item)
As far as I know, treasures from bosses should be fixed items and not randomly generated. For example the lighthouse boss always drops the club.
