Yes it can and I use them in a very similar way in SongKong/Jaikoz as well.
But look at the answers on your How to help people with classical editing? - #14 by mmirG post, the majority complain about the UI and the difficultly of adding relationships, because adding a relationship is more difficult than simply filling in a field that has been presented such as Track Artist. So using more relationships (at least with the current UI) is not going to make things any easier.
Similarly it is more complex for applications to try and decode relationships than just use the standard fields. All music players have an album artist and track artist fields and these need a value, including for classical so make sense for MusicBrainz to at least try to generate these values.
And I do not agree there is no such thing as a Track artist for Classical, there is. It just isn’t a single person, it comprises the Conductor, Performers/Orchestra/Choir on the piece.