The imms explained this a while ago and here is a short summary.

Both ward and dance give you a second chance to get a parry/dodge if you fail the check. That chance is based on str for ward and dodge for dance and is relatively small.

As a result someone who fails a lot of parries will see more chances to get the legacy to kick in and grant a parry. Or the same way for dodge.

For a spear/polearm user remember that spin and distance are checked before parry. So you need to fail spin/distance, then fail parry for the legacy to even have a chance to come into play. For dance you need to fail spin/distance, parry, shield block, and finally dodge before dance comes into play.


I think you have anecdotally experienced it by noticing a bigger difference with mace over sword (sword naturally lands more parries so less opportunity for legacy to come into play and therefore less visible impact).


I have had ward with axes and hands and it made a good difference for both of them.