I'm hoping that in the future maybe these items may somehow be auto transferred to my inventory if dropped by accident OR if the items may just stay on the ground for pick up later. As it is right now these boss fights are instanced and anything that takes place in there is irretrievable unless the boss dies. I think something should be done about this, as I've Googled the issue and apparently many unfortunate players went through the exact same problem.
One last thing. Give us a shortcut key for unequipping items please so we don't have to drag them into our inventory if we want to get naked :p