Focus on highest-value, measurable outcomes
..Not lists of features the platform should support.
Working in an agency, I have personally been on the receiving end of unending lists of MOSCOW prioritised requirements a platform must/should/could have which are often just lists of features with no qualitative or quantitative measures that prove implementing the feature will have a positive effect on the user.
By way of example:
The platform must support WYSIWYG
A slightly better outcome-driven example of the same requirement:
We believe implementing a visual editor will allow authors to create a page with fewer defects during the approval process which should reduce the overall time to create a page meaning our editors can create more pages per day at a higher, more consistent quality. Success will be measured as an increase in the number of pages published per day with a downward trend in the number of defects at approval
Broken down this translates to:
[hypothesis] - [desired outcome] - [how it will be measured]
Thinking in an outcome driven way over lists of features will sharpen your thinking towards developing and prioritising hopefully fewer backlog items that can be measured correctly and add genuine positive benefit rather than be a waste of time and money.