Granted that I cannot even remember the last time that DC or Marvel even attempted to create a 'new' character, I'm all for the replacement angle, especially if it is for characters that need a revamp because they have been in character limbo for ages.
Marvel is better at taking risks when it comes to creating 'new' characters, but 80 percent of the time, these 'new' characters are always white, instead of casting the role to a minority. Is there any reason why the new character Gravity (and I realize that by new, he is at least three years old) was white and not any other race? As much as I would love to see new black characters grace the pages, I would love to see new Asian or Hispanic, or for an even less represented race, the American Indian?
I cannot remember the last time DC tried to create a new character, much less a new minority character. If this Aqualad hangs around for years to come, I want to see him woven into the Aquaman myths so well that when its time for Arther to step down, the new kid can rise to the occasion like Dick has for Bruce.