Cutting to the quick n dirty: 1) Vault of Glass - this expands on the alternate ending of the Paradox story mission. Seeing as the No Time To Explain exotic is next to useless, completing the alternate ending of Paradox unlocks the 370 light version of the Raid with Taken enemies. 2) Crota's End - this can be SIVA infected, as it goes more with the story already in place (SIVA presence is already on the Moon). Crota's End is fundamentally a joke of a Raid, so it would just be a 370 light version with SIVA Splicers. Perhaps add a Kovik-like boss that runs around along with Crota (no raid has two simultaneous bosses). Unlocks after completing SIVA Abomination Heist strike. 3) King's Fall - the Cabal have followed your steps into the Ascendant Realm and taken (no pun intended) over Oryx's true throne. No further explanation necessary. We finally get a Cabal Raid. 380 light. Add and complete two quest missions (first on Mars, then on the Dreadnaught) upon completing KF HM to unlock.