I fully expect the rover to come up with unexpected things. Most every craft we have sent in that direction has. With the subatomic stuff we theorize about it then go looking for proof. With space exploration we theorize then take a look and realize how clueless we really are.
What is important to each of us is an individual thing. For many people the discovery of life or former life on mars is no less important the the discovery of yet another subatomic particle. Both are interesting to me. Personally I am more interested in where cosmology is going with the dark matter and dark energy thing. The fact that what we can see is but a small fraction of what exists.
Maybe some day they will tie it all together.