My thought has been a 20- or 30-year term, with one or two renewals at a nominal fee, would work wonders. Orphaned works basically disappear overnight, and the vast majority of works will have exhausted their useful commercial life within those 20-30 years.
I'd also argue that works eligible for copyright must submit a modifiable edition (eg: source code or a DRM-free copy) that is made available to archivists immediately and the general public once the copyright term expires.
I'd also argue that works eligible for copyright must submit a modifiable edition (eg: source code or a DRM-free copy) that is made available to archivists immediately and the general public once the copyright term expires.