From what I'm remembering, Karmic Dice doesn't affect the # of critical fails. Out of 735 Karmic Dice rolls, a 1 was rolled exactly 5% of the time. I think this is because, in BG3's code, a natural 1 supersedes everything and thus prevents the Karmic Dice correction from happening.
I am not 100% on this one, because 5 critical successes and 7 critical fails isn't a large sample size. That said, it did seem like critical successes were being supressed after the first successful role. 0 critical successes in 70 or so roles is certainly possible, but pretty unlikely (0.95^70 = 0.027 or 2.7%). It was also notable that the critical successes and the first role and the critical failures on all 3 rolls were well within the expected range.
So I'm hearing quite a bit about this Karmic dice issue.
Is there a current consensus that it is best to switch it off?
From what I have read this seems to be the case as apparently the advantage it gives enemy dice rolls outweighs any benefits it gives you.
Seems strange that they would implement such a broken mechanic if what I am reading is accurate.
If enemies benefit from Karmic dice, that would completely undermine the point of the option, at least in combat. Enemy good luck is necessarily player bad luck. Getting hit by an unusually large number of crits of often worse than rolling 1s too often, unless its something like a save or die effect.