To me it crossed the line and just became way too frustratingly and unreasonable. I had no trouble with any of the game's other encounters but this fight was just an endless grating assault of unfair feeling attacks. It really drags down my assessment of the game when it ends on such a painful note.
I mean it was long, but the phases were very different, so it didn't feel overlong to me and it didn't feel unfair to me. For me the game ended on a highnote, also an emotional one because of my final decision after the fight. Not spoiling for others.