Why are Criterion dungeons so hard?

[Jojoya]

I think that part of the problems stems from the fact that it was kinda-ish advertised as normal/ex from the onset?

In the first 6.2 Live Letter, Criterion was described as EX in difficulty and Criterion Savage as Savage in difficulty. Like any new EX/Savage content, players needed to allow for a learning period instead of expecting to be able to faceroll the content as soon as they went in.

I think part of what is throwing players off is the increased personal responsibility in Criterion due to the smaller party size and the resurrection restrictions. It's usually a lot easier to recover in a party of 8 if one player goes down. It's harder when one goes down in a party of 4 and the party is taking heavy damage.