It was cool
Im already running Storm of Souls as a way to bring back all of my small creatures in my Adeline, Resplendent Cathar deck, so I can see this card slotting in immediately as a secondary way to recover from a devastating board wipe
Class cards are relatively new to Magic: The Gathering, being used to represent the fantasy archetypes of Wizard, Fighter, Rogue, and more that D&D has so clearly codified
Nimbus Maze takes the conventional mysteries of a maze, ascending them even further, both literally and figuratively, making it one of the few Magic: The Gathering cards to combine fantasy with something found in the real world
"Spiritual Earth Art - Kurogane" from Cybernetic Revolution
You can cast it for just BRG and it'll enter with three +1/+1 counters, or you can spend more mana on it so it'll be even bigger