Dragonhunter needs vigor somehow, when I fight revenants i feel like I need to dodge too many skills and I get outsustained so fast. Specially if they go retribution line we do like no dmg on them while they still force us to dodge their combos and the fight can take long, so at the end, my endurance and cds will be gone and I will get oneshooted. I need vigor for being able to dodge more often, also because the virtues can be rupted while casting them the class can be easily outplayed without the boon, specially by thieves. That is the main reason I still play scepter focus over bow, this one is too offensive and has lack of sustain considering the meta builds. But then I got another problem, scepter deals too low dmg vs tanky revenant, tanky scrapper, druid.. Should have the dmg buffed for being viable again imo.
You can stack 10 seconds of vigor every 15 seconds by standing in the symbol created by LB skill #4 for the full length of its duration.