I would call Hopper a very good actor but he had a fairly long period when he was into drugs and alcohol and made considerable trouble for everyone, including himself.
I would not call him a 'legend'.
Dennis Hopper certainly had his issues, but in Hollywood, it's hardly a small club.
The number of people on film and video sets who are or were royal pains would be astounding if they could be cataloged.
What would be even more surprising to most people is that many royal pain people are not what you would call household names. I know of an actress with a bad cocaine problem who lost out on two potentially star-making roles because of her drug use. Her name doesn't matter because you haven't heard of her to this day.
At least Mr. Hopper found a road that he could straighten himself out on, however late in life that happened. May he Rest In Peace.
Time alone will decide his legend status.