This is absolutely true.
The ENTIRE POINT of this thread is to determine if luck helps this chance or not.
Well, let's look at how Luck works......
What does worn Luck do ?
1) - It provides higher chances that an item might be generated with more properites;
2) - It provides higher chances that the properties with which an item is generated will have higher intensities;
Now, the above is as far as Luck effects (as I understand...).
Then, there is a third random ballot, whether or not an item is generated with negative properties be them none, 1, 2 or more all on the same item.
Now, as in regards this 3rd ballot that I seem to have understood, it takes into account 1 and 2 which means, that the more properties an item has and the higher intensitites an item has, the more negatives it comes with....
Has anyone seen by any chance "clean" Legendary items coming out of the new legacy revamped Dungeons ?
Assuming that this was possible, probably the chance for this to occur is close to zero, I would suspect.....
Does Luck have any saying in the 3rd ballot ? I do not know but if I had to make a guess, I'd say yes and no at the same time.
Yes in the sense that since Luck affects ballots #1 and #2 where Luck increases # of properties and their intensities, and this then increases the chances of negative penalties coming along, then this suggests to me that the higher the luck, the better the items and the more the negative penalities; and also No, in the sense that having higher Luck does not tell the game to increase chances at "clean" items....
I mean, either an item comes with negative properties or it does not, and if luck prompts for more properties and higher intensities and this as a consequence prompts also for negative properties, then I find it hard to think that at the same time Luck could prompt for "cleaner" items with less or no negative properties even when they have lots of properties and with high intensities...
But all this is just mere assumptions from me, I did not do any testing (it would require a very large number of drops to have some statistical significance and I simply do not have the time for it...).
Personally, I only think a developer could answer to this question.....