OK, database stuff...
I'm not really following that, but I jump in, because I think that the subject of aliases for citations can be easily implemented as a part of GEP 018.

What I mean is that, if a citation object has a (sub)title like attribute, I think it should be available for sorting in the source/citation views of Gramps. And as far as I'm concerned, this should be implemented in a way that does not depend on users using templates or not. Attributes are enough.

These days, I see a lot of indexed sources on FamilySearch that use names to identify records in some indexed data set, like this one below:

"Netherlands, Deaths and Burials, 1668-1945," index, FamilySearch ( : accessed 25 Jun 2013), Franciscus Hendricus Borgsteede, 1845.

I consider this particular citation to be wrong, because this remote cousin died on 06 Nov 1847, and the actual record must have been made that day, or a few days later, but that's my of FS' problem, not yours.

Anyway, I do think it's a nice suggestion to use the citation title as alias the view, where you normally see the volume/page column.