Comment 7 for bug 245594

There is a reason to want single-architecture rebuilds that don't change the source, beyond Debian-specific issues with sourceful NMUs and source ownership. If you're close to release and discover an issue affecting a single architecture, it is beneficial to be able to fix that one architecture without having to change all the others too (and perhaps run across new and unexpected problems). Even further away from release, it may be desirable to reduce the impact on mirrors when fixing single-architecture issues by means of rebuilds, particularly for large packages.

Revving source versions is what we've always done, be it manually or automatically. It means that all architectures have to be rebuilt in step, increasing general load, and I would much prefer to have a way to rebuild single architectures if possible.

I tend to agree with Scott here: we should start enforcing the necessary restrictions so that we're ready for the mechanism. After all, the restrictions are straightforward enough that they can be checked mechanically with Lintian.