Crucible is too long, and the the one shot moves from the boss are cheap if you're making us run through that many rooms each time

Here’s a few posts about a similar topic:

Some good discussion in both threads about the length of the Crucible and why the enjoyability can decline when you’re struggling to kill the Echo Knight.

Important to keep in mind that the Crucible in it’s current form is the foundation for what could become a much more comprehensive feature, and is bound to change as time goes on.

Hard to say what they will or won’t do with it, but this particular feedback has cropped up many times so they’ll be paying attention and thinking about it no doubt.