Ultimately I think umpires call makes sense. As DRS intended use was to remove the howler. Which in the large part it has, I can’t think of a series where it has been questioned as much as this one.
If the decision comes back as umpires call... is it really a howler? Or has the umpire given one view at real time made a “reasonable” decision.
And the the technology can never be proven to be 100% accurate... Trying to prove that an event that never happened would have happened. How can you prove a hypothetical?
The ball presented is purely a visual representation of the most likely path of the ball post impact. If you added the margin for error around it, would it help tell the story better, probably not.