While the code can theoretically be made to do just about anything, all of our services run from a common codebase shared by all Merchants, so there is no way to modify the code for just one Merchant that does not also apply that same modification to every other Merchant as well, since no Merchant runs their own, private copy of the code. We would need to find a way to do what you ask that does not affect or break anything for everyone else. Moreover, while we do appreciate your point, what you are asking is not as trivial modification as it might seem at first glance, and it does indeed open a whole can of worms entailing quite a bit of special, complicated logic; it's not merely a matter of hiding some fields in the cart.
Our shipping calculation routines require information provided in those fields, so we can't simply make those fields optional for everyone and then provide a way to hide them in the layout. We could make them optional only when a Merchant disables USPS rates (and there's a few ways that could happen), but then how would we account for custom Domestic vs. International rates? Okay, so then they're optional only when USPS rates are disabled in any one of several ways, but then the Country field becomes required again when a custom Int'l rate differs from Domestic, except when the sole chosen Shipping destination is the same Country as the Merchant's own Country...
I'm sure there are even more conditionals I haven't even thought of, and all this has to be foolproof and applied into our existing code logic, which may not be trivially amenable to integrating that logic. This doesn't even get into the matter of how to hide those fields and provide a toggle-able switch to do that. All of the time Development would spend accomplishing this special favor would be time taken away from their other tasks, namely, general system-wide improvements and paving the way for future growth and reliability, not to mention far more popularly-requested or trivially-achievable wishlist items for new features.
We can put your request on our list for future consideration; we just can't promise it will get a higher priority than general improvements and more popular/easy new-feature requests.