Superman's not in the same position as Snyder is with Batman, its not really a fair comparison. Superman was pretty cleanly rebooted, with his ultimate origin started at the beginning of the reboot and now just about over in Action. Diggle's not in the position of having to go back in time. It was planned to introduce the scarred Lex and then explain that later. So Diggle's run isn't highlighting any problem insofar as his character, imo. They're doing it this way because they wanted to. Batman, and eventually GL, that'll be another story entirely. But Superman got the full reboot treatment and as it stands now no blanks are necessary to be filled in unless they want to add something specific down the line, as in the Lex situation they developed.