The Zero Fighter trailer makes we wonder... side story to the 1954 film following a Tokyo family during Godzilla's 1954 attack? It would combine new footage, CGI, footage from the original film, stock footage from that era. Most of the film would look modern, but maybe certain sections of the films go entirely into the style of the time: black and white, grainy, scratches - old and new footage artificially aged, of course. I even have a title:
Gojira 1954.
Of course, this idea is more of a 'one-off' film, not exactly conducive to starting a new series.
Rather selfishly, I love the idea of the '54 design replacing he Heisei one as Toho's trademark Godzilla image.