By rewards I don't mean better gear or such, but perhaps unique(ish) cosmetics and emblems for those Sherpas still out there.
Even a simple emblem stating "x Guardians Guided"
Auras for Guiding x activities a week
Ghost shells with perks focused on allies. (Such as increased XP for fire team members during activities)
Unique ornaments for the raid armour during Guided Games (with a high enough GG rating).
Little incentives to reward those that help and guide well, yet not something to be upset about not getting if you're not a guider.
Just an idea.