using statistics in order to decide whether or not to add a filtered index
This is probably not the sort of case where filtered indexes really shine - typically that is when the index represents only a small portion of rows in the table (like, a quarter or less) and in this case the filter predicate matches about three quarters of the table.

That's not to say that you wouldn't get gains here, but it might be a bit of a tricky research project to get good designs. (Then again, indexing is always like that.)

What about the current indexes on the table. Are they being used at the moment? Are they only being used in queries that have the predicate that you mentioned? If so, then it might be an easy win to convert some of your existing indexes to have a filter condition (instead of adding a new, filtered index).

You probably already knew this, but filtered indexes won't be used by where the predicate that matches the filter uses a variable or parameter. https://www.brentozar.com/archive/2013/11/what-you-can-and-cant-do-with-filtered-indexes/