You can create a related field on the Work Order to bring the information from the Manufacturing Order:

Then you show this field on the List  View  of  Work  Orders:

Make your own custom View to inherit and override the standard Odoo View:

Then you will see:

This gives Users the information and let's them know that the Work Order is waiting for products to be made available or picked - they click on the MO to see what is reserved (available, just needs to be picked if multiple step manufacturing is setup) and what is not. 

Optionally:

You can change the definition of the Filter "ready" to remove Work Orders as needed.

You can change the visibility condition for the START button to hide it (also do this on the Manufacturing Order  Work  Orders  tab).