This opinion of D&C's one that I'm on the fence about. I think capeshit families only turn bad if it's all they interact with, you end up with this feeling of them being some high and mighty club like a bunch of Marvel characters are going through right now. IMO the sour taste in his mouth probably is more an Arrowverse thing since that's where his dislike comes from. I never watched them so if anyone wants to explain how they handle it, please go ahead.
DC capes having proteges who later set off on their own is a pretty established thing and removing that removes their legacy. They usually aren't clustered together, most of the Bat-family isn't even in Gotham anymore for example. The Captain Marvel family is pretty silly but they also have the weakness of their powers being divided the more of them transform so it is possible to write them without any of them overpowering the narrative.
He's right about a hypothetical "Daredevil and the Sonar Squad" being a stupid idea but only because it doesn't fit the Marvel Universe where the aliases are tied to individuals rather than being larger than life icons. I'm terrible at explaining this but Captain America is the only notable Marvel cape who shares that quality and it's debatable as Steve Rogers' most successful successor is.....Steve Rogers.