is it possible to view the submitted form
Once executed tasks are archived in a separated database. Contract values are archived but it doesn't mean that it is possible to rebuild the form as there is no guarantee that there is a one to one mapping between form fields/widgets and contract values.
A better approach is to define a
descriptionAfterCompletion on your task (General > Portal property tab). This description can have a small report with values and these descriptions are displayed in the case overview.