There’s nothing more frustrating than losing a rare unique to a Nemesis because you’ve died and so did the Nemesis shortly after and dropped everything on the ground.
The solution is to make it so if you happen to die, he can’t drop items and won’t count towards the progress.
I agree but this has already been posted, at least once (here for example), so please use the search function to find out if what you are posting about has already been brought up.
Going there and voting on it is a better use of your effort.