This is something I've tried to improve with followup updates, without just straight up giving three rooms with ring/artifact/wand choices, which would be very overpowered. As of v2.2 finding a key now means you're guaranteed either some equipment, or a bunch of consumables, at least one of which is experience or transmutation.
I feel like it's better now, but ultimately adding more rooms does mean that specific great ones will become a bit less common, and I wanted to make more use of the crystal key mechanic, rather than having them sometimes not show up in a run at all.