From discussions on this forum, most persons would agree that the problem with arranger players customizing SMFs is that arranger players do not have the technical and musical creative skills to do so.

The same way they are able to use styles is the same way they use SMFs; OOTB and no personalization.

For those of us who actually use the arranger for what it was made for, we customize and make the sound on the gig our own and not just what a prerecorded machine gives us.