With a 15.3-inch display, the 'Big Air' in Apple's MacBook line-up has a simple sales pitch: it's a MacBook Air, embodying everything typically slim, light and portable about that, except it's got ...

CUPERTINO, CALIFORNIA - JUNE 06: Apple CEO Tim Cook stands next to ... Tim Cook’s decision to finally release a MacBook Air with a 15-inch display - the first to do so in the fifteen-year ...

And it's already got me thinking rather fondly about Apple's yet-to-be-released laptop. So what features would a 15-inch MacBook Air need to bring to the table to be an immediate purchase?