Lewis Hamilton
Lewis Hamilton will be looking to win a third drivers' titleGetty Images

Just 112 days on from Lewis Hamilton's crowning as the Formula One world champion, the 2015 season begins in Melbourne with new teams, tracks, drivers and rules, making the campaign as hard to judge as ever.

Pre-season testing in Jerez and Barcelona suggests, once again, that Mercedes will be favourites to retain their drivers' and constructors' titles. An unchanged Williams are their closest rivals going into the opening race on 15 March.

Much-changed driver line-ups at Ferrari and Red Bull only ramp up expectations in either garage after a lean 2014, while McLaren enter the term with a stellar duo of Fernando Alonso and Jenson Button, but little other encouragement from their Honda-powered car.

Toro Rosso, Sauber, Lotus and Force India will all attempt to balance bridging the gap to the main teams, while tackling the financial tightrope that tripped up both Marussia and Caterham, both of whom at least in name are no more. Manor racing take the place of the former.

Bar the drama that naturally engulfs any regular campaign, what can we expect from 2015? IBTimes UK looks at the central themes of the new season.

Daniel Ricciardo
Can Daniel Ricciardo cause an upset this season?

Drivers' champion – Daniel Ricciardo (Red Bull): While Mercedes were over the hills and far away, the Australian rookie won three races in 2014 to firmly establish himself among the runners and riders for the title come the new campaign.

Now the team's number one driver after Sebastian Vettel's departure, Ricciardo carries the responsibility of leading the team's title charge.

Wins in Canada and Belgium showed his quality and though down on power this season, updates throughout the campaign should make Red Bull more competitive than there were in winter testing. He might require the Lewis Hamilton-Nico Rosburg relationship to implode to stand a chance, though.

Constructors' champion – Mercedes: Logically the favourites to retain both titles but the Hamilton-Rosburg axis still has potential to crumble like it threatened to midway through 2014. The reigning constructors' champions enjoyed encouraging winter testing but are yet to show their hand at race pace having yet to do a flat-out run.

Though a lead in the drivers' championship is easily overhauled, consistency is not so easily achieved between two drivers and the Silver Arrows could have the title wrapped up by the climax to the European season in September.

Young pretender - Daniil Kvyat (Red Bull): Record-wreaking Max Verstappen might appear the logical choice ahead of 2015, but in the Red Bull hot seat and after a brilliant debut campaign, Kyvat is set to become the newest star of Formula One.

The fresh-faced 20-year-old became the youngest points scorer in the sport's history in his first race in Australia and went on to finish in the top 10 on seven further occasions. In a car expected to be competitive at the top end, there will be no hiding place.

Greatest hope for 2015 season: That Ferrari, the sleeping giant of Formula One, can enjoy a renaissance. The arrival of Vettel swells the world titles across the team to five alongside Kimi Raikkonen and after an assured winter, though one that saw them lose ground to Mercedes, there is hope the Italian team can muster something resembling a title challenge after years of underachievement. Stability behind the scenes, where much has changed, would be a start.

Great fear for 2015 season: Where do you start? F1 could do without the rotating conveyor belt of teams dropping in and out of the sport, though the sad demise of Caterham showed the struggles some have just surviving.

In addition, after Jules Bianchi's crash at the Japanese Grand Prix, which continues to leave the French driver in a coma, the safety of F1 continues to be a subject for debate. Finally, after a subdued winter test in Spain, McLaren are slipping ever closer to being totally uncompetitive in 2015, despite their all-star cast. Another major team suffering a downturn in fortunes.