Great question.

For our team, we say yes to whatever solves the biggest pain, for most of our users.

We discover this by reaching out to customers, and doing a lot of listening. We're trying to answer two questions:

1) What is your biggest pain in your daily work?

2) What is your biggest pain in our software?

#1 usually leads to new features.

#2 usually leads to revisions of what we have already.