All of that is not doable via offering source rpms, so, maybe we can get rid of src rpms at all later ...
Currently osc/obs webfrontend is for novell accounts only, and also a seperate tool if one wants to really see the history of the package (osc)
So the srpms fill an important niche, people from upstream projects getting bugreports can simply go ahead, download the source rpm and check the .spec file for obvious mistakes in the building process and/or check the patches applied.
Before dumping source rpms for saving space, which is somewhat questionable looking at the huge space and traffic the home: repositories generate, people need an anonymous read access, I don't think any other distribution forces something like this on external people.
Karsten