There seem to be lot of momentum in discussions about making Debian testing more attractive to users on debian-devel mailing list (see Lucas's summary for summary of the lengthy discussion).
One of the raised points there is that Debian misses equivalent of Ubuntu's PPA or openSUSE build service. As Debian is usually about do-ocracy, it will be there once it will be implemented, but I still don't think it is always useful to have such thing.
The problem with both (but this is especially the case for openSUSE build service) is that you need to add dozens of home: projects with questionable quality of the software. This usually leads to horrible mess, especially in case of incompatible libraries with different build options (anybody using wxWidgets?).
It can definitely lower barrier for people to create packages for the distro, but is it really good to lower barrier that much? I'd really prefer new things to be uploaded to Debian itself without need to use any external repositories, it would ensure at least some level of quality and compatibility with other packages.
