Random distribution curves can be interesting. Mathematically, it's (unlikely but) entirely possible for someone to flip a coin and always get heads.
Our developers are aware of and looking at ways to address outlier cases where even a greatly increased chance to drop isn't enough.
You don't have to look for ways to address this, you already created one before in TBC, it's called Badge of Justice.
Just allow exchange x number of Badges for whatever you can get from that loot table, and limiting only 1 badge/boss/week. No more RNG crap, no DS needing/trading issue either, all vendor gears = bop.
But I know your evil minds, you want people to keep running 5.1 contents during 5.2 so people who are slow or behind will be carried for those who ran the same !@#$ every week, you just don't want your LFR to go empty and end up with 3hrs wait time.