The gap in pedigree between Hamilton and Valtteri Bottas, Nico Rosberg's replacement, is stark.
One is a triple world champion, the other has yet to win a race in 77 starts. Mercedes' lack of expectation that Bottas can rival Hamilton is reflected in their reluctance to offer him more than a one-year contract.
3. Stoffel Vandoorne will justify the hype
The word in the paddock is that the Belgian, given his first F1 chance at McLaren, can be exhilarating as Red Bull's Max Verstappen on his day.
He was renowned, throughout his time in the junior GP2 series, as a master of audacious overtaking. The pity is that his car, beset once more by problems with its Honda engine, looks far off the pace.
4. Wet-weather standing starts
Endless safety-car laps in torrential rain, as happened in Brazil last year, have been consigned to history. A normal standing start will now be formed once the track has been deemed safe to race again.
It is designed to give fans the chance to see a real start, if conditions are too wet at the outset.
5. Gigantic rear tyres
Teams are concerned about whether the garages in Melbourne this week will be large enough to accommodate the colossal rear tyres mandated by the latest regulation changes.
They are 25 per cent wider than last year, giving a retro 1980s look, and with a very low rate of degradation, so as not to detract from the cars' enhanced performance.
