Serene Rejuvenation is a minor trait in the Salvation line. It makes it so the Revenant's outgoing healing to allies is increased, but more importantly, it makes the Natural Harmony apply Alacrity to allies in its radius. Selfless Amplification simply converts your healing power to outgoing healing.
The problem I find with this is that Serene Rejuvenation is a minor trait that basically forces the Revenant to use Ventari, while Selfless Amplification is useful to any Revenant builds with healing power. Minor traits should account for all kinds of builds, which is why I think Selfless Amplification should be a minor trait instead of a GM. Likewise, many GM traits define builds by fundamentally changing the way certain skills work (just look at Holosmith). As a result, Serene Rejuvenation should be placed as an optional GM major trait. This would make builds not using Ventari not feel so kitten by taking the Salvation line (a large portion of the line is selfish defensive traits anyway).