They need to just do:

Story mode = Story + no rewards. Easy difficult so the more casual players can experience the lore without having a static.

Normal mode = Difficulty maybe something around ScoB with echo. Good gear rewards, will probably require a static until overgeared and put into DF. Nerfs possible.

Savage mode = Hardest difficulty for the hardcore. Static required. Best weapon and gear in the game. No nerfs. No DF.

Savage must offer better gear. Period. Or else it will be ignored by 99.9% of the population.