Pass argument to node_add function

Hi,
my needing is to pass arguments to the node_add form.
Standard content creation passes through a link node/add/node_type that calls node_add defined in node.pages.inc; this function calls directly drupal_get_form with 2 arguments, the nodetype and a node object.
drupal_get_form gives the possibility to add other arguments and puts all the arguments except the first one in $form_state['build_info']['args']
Is there a reason to pass only those 2 arguments and to prevent adding more than the form_id? Why can't we give the same opportunity, given from drupal_get_form, using node_add?
In attachment, a patch to evaluate.
Bye
Corrado