I'd make class exotics lore specific. They would be difficult as fek to earn. Titans: The actual mark of Saint-14, earned by a long quest that leads back to the tomb. Warlocks: Toland the Shattered' bond, earned by a quest that takes you back to Luna to find Tolands body. Hunters: Tallulah Fairwind/ Andal Brask/ Cayde-6's cloak (not that knock-off eververse one), earned by talking to Shiro-4 and Amanda, they tell you to go a quest in the cosmodrome and visit Cayde's grave.
Like these ideas. For the cause cloak, You should go back to the area where caydes secret chests are.
Amanda already has Cayde's cloak...
The Cosmodrome??what are you smoking??? Something The Drifter gave you?