True, but it increases disrupt chances, something you really want. Depends on one's playstile. WP has low mobility, if you are comfortable in staying safe at range (without being tempted to get in the heat) you will gain benefit from high willpower: crits with high wp are significant IMO.
I have been often joked because of slotting willpower talis, well, that's my playstile, at least pre-invader