Moving Things on a Canvas: New commands $canvas moveto, $canvas imove and $canvas rchars for moving and manipulating canvas items.
Perhaps this is something that can be used by the pd core instead of deleting then redrawing? I think there would need to be some sort of compile time or runtime check for the TK version though.
In any case, I'm still interested in ways to abstract the raw guilt tcl from the core usage in order to provide a generic interface for guis communication in libpd, so looking into this could be part of that...