Suggestion: "What Killed Me" Button on the UI
When doing harder content, I certainly expect death to happen as I am learning the mechanics of a fight. There's plenty of fights in the game that probably cannot be done by most people on their first try, even if they've read a guide beforehand.
That being said, however, I honestly find the most frustrating moments in the game to be either when I have died because of animation locks or when I died and have a lack of information about the cause of my death.
Animation locks are, as far as I'm aware, here to stay and I have to simply deal with it and adjust.
The latter, however, is far more frustrating to me. When it comes to a pretty difficult scenario like The Dark Within, I'm perfectly fine with dying as I learn the mechanics because I can often tell visually what mistake I made and how to improve. There are fights, however, where there is not a very clear indicator or a very short time to notice something and thus dying is more frustrating because I have zero idea what happened and feel cheated as a result. Combat logs are not very helpful because they fill incredibly quickly and the current chat system's tendency to auto-scroll makes that information effectively useless to most players.
I would really like to see an addition to the UI similar to WoW and a few other MMOs where I can click a button and see what attack or hazard caused my death. I think that WoW's is actually insufficient because it simply shows the damage numbers. Having a brief blurb about the mechanic would probably be more useful to the player so that they can avoid that mechanic in the future. An indicator of how that damage was multiplied by vulnerability stack would also probably be useful.
I think a "How did I Die" button would be a positive for the game for players to learn mechanics and understand what mistakes are being made so that they can adjust and improve.