There is clearly an issue with Nuri's Mini Dungeon, and that is that it is well, not being played. I know this because I can't find a game to run it with. From a business perspective (and at 3 plat per run, that is what it is), this is bad for both STS and for Fluff. I see three "issues" limiting the amount of players and the pink drops:
1) It cost plat to run.
2) The drop rates are extremely low because Nuri's pink drop rates are low.
3) It is actually a pretty tough dungeon. (I can't solo it using thrasher on my 56)
Now I see this like the old saying, service, price and quality, pick two out of three. So, looking at it from that business perspective, number 1 can not be eliminated. Upping the pink drop rate is a possibility, but if you over do it, the pinks flood the market, people just buy em with gold, and there really is no reason to run the dungeon after a short spike in running. But number three, that's where the money is. By making it easier, players like Fluff will be able to solo it (after paying for a thrashers of course) which will lead to more games. No more saying, well, I would play but there are no active games. But wait, there's more. When you do have groups, they will kill the bosses at a faster rate, and that means less time between remakes (SPENDING MORE PLAT). Over time, this will make the drop rate appear higher as people will actually be playing the dungeon, instead of say, refreshing the join screen to see if anyone else is playing the dungeon.