[itsme]

In my understanding the goal is to integrate transposable scores in standard notation into MobileSheets.
Native support of a notation file format would be absolutely great and I fully support that request (but I know that it is not easy to implement).

To allow transposing the musical semantic is required. Transposing is not only shifting notes up or down. Stem direction, accidentals and so on have to be considered.
File formats like .ABC, .MSCZ (MuseScore) or MusicXML (and many others) specify that musical context. After the conversion to .SVG the musical semantic is not available anymore, .SVG describes dots and lines placed on a rectangle. Please correct me if I'm wrong. So imho in the workflows you are describing, .SVG is something like an intermediate format. The way how MSP comes from a notation file to the image on the screen should not be important for the user.