Yea unfortunately looter and efficiency isn't helping as it is proposed to do. It's obvious the loot was changed and anyone that kills a decent amount of mobs can see that.
My guess is that Looter works just as it should. Looter isn't there to boost return, its there to
reduce unefficiency to the build up of loot.
Imo, one of the reasons why its there is due to when someone do a new report to gambling authority
about EU is just gambling, they can point at the composition of skills and attributes and say
that due to being so low, impression could be that it contain some randomness but it doesn't.
This is the reason why Looter prof stands have skills that are more or less impossible to max out
and we can't even gain them in the interaction related to that prof stand.
Earlier we had mainly attributes that made it impossible for someone to max out prof stands,
now there are also skills included. Sure, you can max out what is shown in the UI but not the
part where each individual skill and attribute have an influence.