The number of people who even understand the issue is small, and the number of people who would forcefully disable the driver signing is even smaller, but it SHOULD be an option for people who want to do it. It's extremely frustrating for those of us who, knowing the risks -- for whatever reason -- want to load an unsigned driver.
This is also not an oversight. At some point in the betas, you could use bcdedit and disable the checking. This is reasonable, and makes sense. You should be able to do that from a technical standpoint. However sometime before RTM, they specifically disabled the ability to disable driver signing permanently with bcdedit.
The real question is, why? I think it was either a money-grab for the cert authorities, or a way to force more control over the environment, to the end of trying to impede the efforts of homebrew drivers and hackers -- groups of people that historically don't pour a lot of money into Microsoft's pockets.