I believe "Seeker" is the best name for the Mars 2020 rover because of how it represents our goals in "seeking" new opportunities and science on Mars. Regardless of the body we travel to, our goal is the same, to seek information for the benefit of humanity and advance our knowledge of the universe. The Lunar astronauts, the astronauts on the International Space Station, the first Martian astronauts, and everyone else can rest assured knowing they're backed by decades of scientific innovation and data that came from our fundamental goal; Seeking the unknown.