The mappings for the datainput parameters configured inside an user tasks should be created automatically to the content field to be accesible from the Human Task component. This automatic step should avoid manual mappings and if the user wants to customize the mappings he can continue using the content tag inside the mappings.
The end result will be:
1) if you use the content attribute inside the mappings of the human task you can manually create the mappings between the datainputs and the content for that specific tasks
2) if you ommit the content attribute in the datainputs parameters the mapping will be done automatically using all the datainputs defined in the task.