Heavy RNG-based loot system must be changed.
No matter how effort you grind for your desired loot. If you're not blessed with good RNG, you'll end up frustrated eventually. Imagine grinding T13 with "pug" parties who clear 2/7 then the loot you wanted isn't showing up.
I suggest there must be a number of "coins" or "tokens" system that can be traded with your desired loot. Some people going up empty-handed most of the time because of this hefty RNG-based system.
Some working people doesn't tend to "grind" hours of doing it.
Please hear my suggestion Square-Enix Team. I would be glad if you do so. This is a customer's suggestion.