Bungie removed elemental primaries for game purposes to make other weapons more viable, but imagine what our characters and the Vanguard think about this. Cayde 6: "Hey remember those awesome primaries that dealt elemental damage and help our guardians kill shielded enemies? Why did we stop using those?" Ikora: "I don't say this that often, but you have a point Cayde, why did we stop using those? They were very helpful in our fight against the darkness. I know! Since we can create many copies of the Zhalo Supercell and that has Arc properties. Why don't we take the blueprint for Zhalo's arc properties and put it in other primaries to help our guardians fight the darkness!" Zavala: "Excellent thinking Ikora! And we also make various other vanguard weapons with other elements, if we can figure out how Zhalo has elemental properties as a primary, we can take the other elemental mechanisms and put them into all primaries we sell! This is an amazing moment for the Vanguard, we shall soon be able to create stronger weapons for our Guardians! Ikora, get your warlocks to start studying the Zhalo and reverse engineering. Cayde, summon some guardians to bring us their old elemental primaries so we can see how they work." Deej: "Cancel those orders Zavala, we here at Bungie won't allow players to use elemental primaries anymore." Zavala: "What!? Why? It will help in our fight against the darkness!" Deej: "Sorry, they make our game too easy, we'll only bring them back when we desperately need to get players excited again. Until then! -Deej"