You've shared some great thoughts on how the supply drops in your game could be improved to maintain their uniqueness and usefulness. You rightly point out that the scarcity of items in these drops sets them apart from the more common chests scattered around the map, ensuring that they remain valuable.
I agree with your suggestion to enhance the variety of items in these supply drops. The idea of replacing the less useful food item with a more random, miscellaneous item is intriguing. This could include anything that doesn't fall under the categories of the powerful armor piece and weapon currently offered.
Regarding the inclusion of crossbows, your perspective makes sense. Since they are relatively common in normal chests, adding them to loot drops might diminish the drops' significance. It's important that these special drops offer items that are not easily found elsewhere.
Your examples of interesting items are well thought out. The idea of having suspicious stew with varying positive effects is unique. Including items like TNT, which you've identified as both useful and powerful, could add excitement to the drops. The possibility of finding enchanted books is also appealing, especially now that anvils are usable. Offering rare or powerful enchantments like fire aspect or flame, exclusive to these drops, would add an extra layer of allure without being overly disruptive to the game's balance.
Overall, these changes could greatly enhance the appeal and strategic importance of loot drops in your game.