The 12-year gap and the 5-year gap

[Gangbuster]

i think the whole 12 year gap thing is a bit of a mistake, it sort of dehumanises superman, like in the orginal radio show, when superman comes to earth as an adult and then takes on the "disguise" of clark kent..

... thats not superman, thats the martian manhunter

I've only listened to the first few radio episodes, but recently I discovered that Superman coming to earth as an adult was never referred to again: the radio show "fixed" it later. In the 1942 retelling of Superman's origin, he came as a baby and the Kents were his parents. See here: http://www.supermanhomepage.com/radio/radio.php?topic=radio-episode-list

[Permanus]

By contrast, the 5-year break became the titular conceit of Superman Returns. 

"Titular conceit". I really like that. Nice turn of phrase.