Hercules has her uses, but most of it comes from her Relic weapon. She gains +30 Burst from one of her skills, which allows her to replace Shingen for Provisional Forest builds if you want.

The main advantages are that Hercules' first skill is a pretty strong nuke skill, and that her Relic weapon causes up to 25% Def Down on Burst (at LMB). Meanwhile, Shingen's Relic weapon gives her +30 Burst from Bursting (at LMB), which is very difficult to make use out of except in Wind builds.