There are no personal revelations other than feelings arising from the work itself
There's no such thing as a small part. There are just small actors.
In drama, the characters should determine the story. In melodrama, the story determines the characters.
All good work requires self-revelation.
I only said 'Titanic' is unwatchable because one can not watch it.
The varying physical characteristics of the actors may also necessitate changes. Sean Connery is six feet four. Dustin Hoffman isn't.