Who will benefit from this work (customer or internally)? _
What is the benefit you think this will create for _?
Have you proven this benefit is important to _?
If you had to benefits in half, what would it be?
If you had to cut those customer benefits in half again, what would it be?
Now, brainstorm with developers to answer "what is the smallest and quickest work we can do to deploy this change so we can see if it is the benefit is actually what we think it will be?"
Use this work as the first increment of work and go completely from development to release to testing that it actually was a benefit.