Comment by gpm

And trying to design an optimal vehicle for mars is how you bloat the costs of your rover program by many many millions of dollars. Downmass is expensive, engineering is more expensive. The result of that is to take advantage of the fact that "mass cures a lot of sins" (Paul Wooster, SpaceX Principal Mars Development Engineer at Mars Society Convention 2019).

> true all-terrain body-on-frame construction

Why would you prefer this? It's just a form of construction that requires more materials, and results in a weak body that can be damaged. Furthermore, we get all the materials for the unibody design (lots of stainless steel) free from starships that won't return, and the material is easy to work with.

Mar's terrain is pretty simple. Rocks, and sand. We almost certainly will choose not to land on sand, so we only really need to deal with rocks. Cybertruck, really any earth vehicle with a reasonable clearance, should be able to deal with that well enough, maybe with some custom tires.

Thermal management, and problems relating to pressurization, are the only things that jump out as me as real difficulties. Neither sounds like it needs fundamental reworks though.