May I suggest adding a wildcard type to the describe attributes, for properties used to describe any resource type? This can be added very simply with no significant changes - all I did in my local copy is changed in the default renderer (SparqlEngine/ResultRenderer/Default.php) describeGraph function (line 156) to initialise $list instead of null with:
$list = $sparql_describe['*'];
..then merge the array instead of assignment at line 160:
$list = array_merge($list, $sparql_describe[$strLuri]);