In 'rwby man of steel fanfiction', perhaps an interesting aspect is the character crossovers. Imagine Ruby Rose with some of Superman's powers or Clark Kent interacting with the RWBY team at Beacon Academy. It could lead to some really cool scenarios where they learn from each other's strengths and weaknesses. Also, the fanfiction might explore how the values of the two universes, like heroism in RWBY and the hope that Superman represents, can merge and create new storylines.
Well, one interesting idea could be the combination of the RWBY universe's unique character abilities with the epic scale of the Man of Steel story. Maybe characters from RWBY having to face challenges similar to what Superman does in Man of Steel, like dealing with powerful foes that threaten their world. Another idea might be the exploration of how the different Dust types in RWBY could interact with the technology and powers in the Man of Steel world.
Some interesting ideas could revolve around the settings. The RWBY world has its own distinct locations, and mixing them with the cityscapes and landscapes from Man of Steel could be fascinating. For example, a battle taking place in Vale with the destruction and chaos similar to what we see in Metropolis during a fight in Man of Steel. Additionally, the fanfiction might play with the concept of how the RWBY characters' weapons would fare against the super - powered threats from the Man of Steel universe.