Next Avengers: Heroes of Tomorrow (2008)

The children of the Avengers are trained to fight like their parents once did, but there's been nothing to fight for or against until now…
The film is aimed at a young audience, but in my experience even kids can spot plot holes and question why things don't ring true when something else is taken as a given. Heroes of Tomorrow is filled with those kinds of errors.
On the plus side, the young heroes weren't as annoying as they could've been, given their motivations and their age. In fact, they were mostly bland. The only one I found slightly interesting was Thor's daughter, Thoruun, with her impulsiveness and her father's anachronistic traits.
It spends a little more time on characterisation than most of the Marvel animations I've seen recently, but it ends in the usual way.

2½ sins of the surrogate father out of 5