I think superheroes need to pass the torch to maybe those who have similiar, ideals, personalities, powers etc. If they passed the torch it would help character development and have new faces in the comics, mo pun intended.  And this is exactly the reason why I wouldn't mind if comic book characters aged.

I love when they age, it does not have to be much but just something to show that they are growing mentally or physically. The first thing I thought of was Spider-man being  more of adult, he could not be that young high schooler forever. Change for a character is good, it makes them seem more human.

I agree, Like Bruce Wayne needs to retire.

I love legacy heroes. This thread even inspired me to make a list of them: Great Legacy Heroes
  
Suggestions for additions welcome.

I like those legacy heroes.