It becomes hard to scale a known superhero b/c all of their powers were presented by different artists/writers across decades with wild swings up and down depending on where the story needed to be. They weren't developed by game designers with point buy systems. My suggestion would be to rejigger the point buying system to a maxed out character with points appropriate for an Epic Level campaign as a goal and to put that to one side, but to place the player somewhere in the middle or the bottom, and add and subtract power across an entire campaign (so that a cerain budget of points can be reallocated). They could occasionally borrow/leverage these other powers depending on need (Fate?). This would hopefully keep the player and the GM invested in a storyline that challenges and inspires them.