It always feels disproportionately difficult, particularly compared to the Yog fight. If you don’t kill the spawners, you will have a harder fight, but you won’t get combo’d to death in a few turns from bad luck. I was at ~40 hp before my last move.
My main mistake here was during a blast wave wand when I shouldn’t have, because I forgot about knockback paralysis (usually it’s not a big deal, but here it ran me into 3-4 other paralyzing attacks).
That being said, the Rock density is a pretty frequent issue because there are twice as many attacks as normal. There have been times when the Sappers and Geomancer have attacked at the same time, so there literally is no safe square to move to even in completely open space. More commonly, they will attack within a turn or two of each other, before you get to clear your surroundings. This is the fundamental challenge with this fight.