Imagine a loot filter system with a separate tab in the inventory where you decide what happens to the items you pick up. You can check ‘Gold’ or ‘Salvage,’ or uncheck either to keep the item. The list would be simple: White, Blue, Yellow, Legendaries, and Uniques.
If everything is set to ‘Salvage,’ the only items kept in the inventory would be Uniques with greater affixes, Mythic Uniques and Ancestral Legendaries. The rest would be salvaged as soon as they are picked up. If a legendary item has an upgrade for a codex, that aspect would be upgraded in the codex just like it is now.
This would greatly improve the quality of life in the game, and I know many people would appreciate it. It’s not too advanced either—somewhat limited but still a significant quality-of-life improvement.
One more thing that might be a bit much, but could be useful, is having pets pick up items that are set to either ‘Gold’ or ‘Salvage’.