Might I mention that from a lore perspective, bringing back Sepiks, Sekrion and Omnigul wouldn't make sense. All three Strikes have been confirmed to have already "happened" in TTK. We find Sepiks' remains in the Cayde's Stash mission, Echo Chamber is built around the fact that we took out Sekrion, and in The Promethean Code, Cayde says: "Omnigul's screams have already been silenced." Now before anyone starts spouting hate at me for not wanting to have variety in Nightfalls, I would like to add that I infact do. The thing is, I am such a huge lore nerd that I cannot help but point things like these out. Also, Phogoth and Aksor could always return, as they are not, to my knowledge, included in any Quests, or otherwise mentioned to have been defeated.