I think the underlying game foundations (and especially the ending) led to more questions being asked than answers being provided. How does Mario-and-Cappy's game dynamic work, ethically? Especially when most the baddies that they co-opt are sentient, sapient life forms on the planet they inhabit? Should we even WANT Mario to succeed? I am not sure who the bad guys are in this game anymore.
... Or maybe I'm overthinking it.
Yes, I know I'm not the first person to make this joke.