I originally designed these in 2017. It's a toy concept of a line of actions figures, that I would have loved to of had when I was a child.
I would want the ball jointed areas to be extremely strong, so when swapping the limbs they won't snap off - ruining the figure. That's why I think a steel ball jointed frame is perfect, so the toy idea can function plus to prevent breaking.
A toy is never the same when parts have to be glued together.