Maybe I'm just overly curious about how the game generates sunken crypts/burial chambers.

I would assume they are procedurally generated (kind of like how Warframe builds each mission by stitching together rooms randomly) vs. randomly chosen from a list of prebuilt dungeons.

With that said, I hope the devs give the dungeons a little love in the future. After a certain point, there is no reason whatsoever to go into a burial chamber, and there was NEVER any real reason to go into a troll cave.