Revivalist’s Revive Speed Effect
Probably the most important Trait for those planning on playing a fair bit of co-op but aren’t strong enough to carry fights on your own if your team-mates perish in a boss fight. A lot of Boss attacks are timed such that you have incredibly small windows, if any, to stand still without getting struck down, especially if you are their primary focus, which becomes more likely when you lose a teammate and guaranteed if you loose both. Throw some spawned adds into the mix, and it can be damn near impossible to have enough time to shoot, let alone revive team mates.
Having Revivalist fully maxed out makes a massive difference, cutting the time needed in half and making it far easier to keep difficult fights from failing at critical moments.
How to Find the Revivalist Trait
The Revivalist trait will unlock once you have revived team mates 10 times collectively. This does not have to be in the same play through and will happen fairly quickly if you play co-op often.
If you are in a rush to unlock it, you can have a teammate help you by downing them and reviving them in Ward 13.