Honestly, legacy heroes never made a whole lot of sense to me in the first place. Most people want to establish their
own identity, and in today's culture with social media people more than ever are obsessed with their persona as part of their "brand."
Granted certain
do characters make sense. Captain America is an Uber patriot identity created by the U.S. government. He is
propaganda. (This is not a dig at Steve Rogers or anyone else that held the shield, FYI. I like Steve, Sam and Bucky.) The U.S. government can (and has) passed the mantle onto anyone they see fit for the role. (Ie: John Walker)
Any hero that has a
consistant sidekick. It makes sense that said sidekick is
training to take over the mantle. Otherwise, you're just needlessly endangering a minor.
ie: Dick Grayson becoming Batman.
The superhero has a son or daughter who feels obligated to carry on the family legacy (had to have a great relationship with hero parent though, not one filled with resent. Ie: Mayday Parker, Spider-Girl.) I really wish Wolverine and X-23 spent more time on panel together, because Laura taking on the Wolverine mantle just feels so artificial (imo.)
Any character who is received with a mixed or extremely negative public opinion however, would probably NOT be a legacy hero. Spider-man is often feared and hated by the public, and considering that in recent years he is treated as a
laughingstock by the
rest of the superhero community (heroes like Luke Cage, etc.) It becomes rather unbelievable that anyone would
want to carry on that mantle
in the 616. (The film "Into the Spiderverse" solved it by showing us the world viewed Parker as both a great hero AND a celebrity, so Miles as a legacy hero makes sense in this
one instance.)
Legacy villains on the other hand, DO make sense. A lot of villains chose crime because they think robbing people is easier than using their powers legitimately. (Electro could be a self made millionaire if he used his abilities to generate electrical power for people that need it... ) But villains don't think like that, so
of course they would steal another villain's gimmick and weaponry if given half a chance! (Ie: Jason Macendale killing and taking over as the new Hobgoblin, Bart Hamilton as the third Green Goblin or 3 out of the 4 Mister Fears.) Villains also have a habit of dying due to their own evil machinations, so it also makes sense that an identity would be up for grabs by lazy uncreative baddies hoping to get rich quick.