Looks promising.
When evaluating a factor, I typically assess its incremental contribution relative to a baseline ranking (e.g., my existing ranking system). It would be useful to allow users to specify a baseline ranking model and then measure the marginal change in IC and other performance statistics after incorporating the candidate factor into that baseline.
This would be a nice addition (perhaps as a future feature) to help quantify the factor’s incremental predictive power rather than evaluating it in isolation.