I don't see a fault in current system, other than the tokens eating inventory space. You are guaranteed at least 1 drop of each item on the loot table every single clear. If you want to be as efficient as possible and eliminate a chance of bad luck, form a premade group and farm a floor until everyone has received what they want for the week. If you want to optimise it further, form a group consisting of people who want different items.

I like being able to plan which item I will get which week.