Inkscape provides an extension "dia.inx" that allows Dia files to be read by Inkscape. It is only enabled if dia is installed. I think "Suggests: dia" is fine here, because it adds extra functionality to Inkscape.
I can't see an obvious reason for "Suggests: skencil". The import/export extensions don't require it any more. "Suggests: python" is also clearly not needed. The "Recommends: python-*" explicitly list all non-standard python modules that would normally be needed for Inkscape extension scripts.
Inkscape provides an extension "dia.inx" that allows Dia files to be read by Inkscape. It is only enabled if dia is installed. I think "Suggests: dia" is fine here, because it adds extra functionality to Inkscape.
I can't see an obvious reason for "Suggests: skencil". The import/export extensions don't require it any more. "Suggests: python" is also clearly not needed. The "Recommends: python-*" explicitly list all non-standard python modules that would normally be needed for Inkscape extension scripts.