well the devs said Survival Mode is not returning I would like to see the base items from Survival Mode placed as random drops in new upcoming content
Best place to put them is in the Stabilizer Duo or the Vault (or both). There are a few items that used to only ever drop in survival mode in the Stabilizer Duo (the Standard Room Divider comes to mind).
Though I'd love to see them in vault or Stabilizer, it's not fair to people that did SM to get them. If there was a bonus alternate loot box that dropped in end-game Elite content, it might be a good compromise. It would just be a chance to get that drop, and when opened it would have a random style, base item, or pet.
Even though I didn't do survival mode or do Elite, I would have to agree. Put the stuff from Survival Mode into the Elite content. We were supposed to have 12 different Survival Mode instances and one would be featured each month and they would rotate. IF you missed something in one instance, you would have to wait until it came back in its rotation.
There were a number of players that ran SM to get the base items so that they could sell the items on the broker.