I've been noticing that it appears the loot drops have been "balanced" regardless of what type it is. For instance, epic pieces that normally are there 100% of the time, have a 7% chance of dropping on a 25 probability loot set. That would need to be fixed to your preference. I'm still trying to wrap my mind around what probability vs chance means.
They can all be fixed, and I believe it really is to the preference of the Admin. I can't imagine Emu devs dictating how often your loot drops.
Wiki.