I was looking for a discussion such as this.  For the vast majority of the game, I have had no complaints over the dice roller and RNG. 
  
Until I got to 6-3: Scaling Mhar Massif.  I've played through that quest about 15 plus times now, and still have not beat it.  I will grant my team is likely not optimized, but going purely on dice rolls and type of dice (d4 vs d6 vs d8 etc etc) I have found that a larger than average percentage of time 1/3 to 1/2 of my dice rolls a 1 or 2.  Maybe I just notice it more because of the condition that makes those zeroes, but when I consistently am rolling 4-5 dice because of blessings and other effects, primarily d8 or above, and consistently two to three of those dice return a 1 or 2 every single roll it begins to feel like more than just bad luck.