Without wheels, the rover can not rove. Pretty much makes it useless if the wheels are broke, correct? Just like any vehicle, the wheel/tire is the most important piece regarding performance. Without good contact, all that fancy machinery won't do a thing.

Definitely, but couldn't you argue the same about other important components? For example, without an engine/motor, even the fanciest wheels will get you nowhere. I think it's somewhat of a paradoxical argument.

So the way I see it is that all of the major components are equally important, but you want to optimize your overall design to be both light and reliable.

Of course you could, that's why you don't skimp on those things. You can get by with a crappy interior, but things like wheels/tires/transmission/engine are high priority. That's my whole point here, it doesn't look like the wheels were over engineered enough, but I'm not a rocket scientist.

That wasn't clear from your original comment though. In case of the rover, other important things include comms/nav, movement controller, power source, and sensors.