As a musician, a large part of the reason I bought a NetMD walkman was to be able to easily record and edit live music. Minidisc is a great format for this purpose.
The lack of support for uploading recorded music to a computer is a major limitation, and as it is essential for musicians to be able to digitize music in order to sample, mix, and add effects, the current implementation of minidisc just doesn't cut it. Having to copy music to a computer in real time after it's already been recorded in real time results in a loss in quality and a loss in precious time.
The ability to upload recorded tracks via USB to a computer would vastly broaden the range of minidisc applications and can only be a sound business decision.
To boot, it must be blatantly obvious, looking back at the history of technology, that NetMD will eventually be hacked and made to suit the needs and desires of its users, which include digital upload capability. Possibly even before that happens, Sony's competitors will probably respond to the desires of their customers in providing such capability, unless Sony takes the cowardly legal road to quashing such free market activity.
The argument that digital upload capability would allow illegal reproduction of music is rather moot, as CD burners are ubiquitous and just as easy to use to distribute music. Even so, upload capability could be implemented to avoid such reproduction by only allowing the upload of sound recorded directly to minidisc via the microphone or line in jacks.
In short, give us USB upload capability. It can only be a good thing for Sony and its customers.