I understand the mapping of the parameters in a Template Canvas dictionary to parameters in the templates. However, is there a way to send the entire dictionary to the template to allow the template to access the dictionary data without mapping each parameter?
No, because datasets cannot contain jython dictionaries, so the json encoding is a work-around. And Vision has no support for jython dictionaries as actual custom properties. (I've lobbied privately for Document property support and was shot down. 
But that still wouldn't help here, because datasets can't hold Documents either.)
Thanks, Phil 