Lootsplosions are just one of the reasons why I love Borderlands and Battleborn. It’s a big firework explosion that visually rewards you for killing a boss. The physics behind it? Not so much. It’s one thing for economy items to fall off the edge but it can be frustrating to see loot fall off into the abyss as well. I haven’t really had too much of an issue with this in Battleborn (fights like the Varelsi Maligner in The Saboteur, stuff can be missed because it falls off the edge and even though it can be restrieved, it is still easily missable), but it was definitely a thing in Borderlands 2. But stuff that drops that is rare/epic or higher and somehow gets missed should be sent to a lost items kiosk (more a suggestion towards BL3), or given to you at the end of the mission regardless.
Bosses like Geoff also like to spit out orbs in a ring around them, and he will often knock you back when he retreats as you have to get in close to pick them up.
A quick idea offhand for bosses like Rendain, (where it jumps straight into a cutscene after each health threshold) would be to have a visual pickup/“mission ends” countdown where you get a reasonable amount of time to pick everything up which is proportionate to the number of players (longer for fewer players). Maybe even a proximty timer as opposed to the yellow orbs hitting the ground and immediately starting to decay so if you are getting knocked back when the boss dies, you aren’t getting penalised for it.