Darren Woods’ appointment as the new chief executive of ExxonMobil was one of the most predictable events of 2016, telegraphed when he was appointed the company’s president a year ago. The course he will take now he has the job is much less certain.  Carrying on as before is certainly an option. Exxon, the world’s largest listed oil group by market capitalisation, is not in an immediate crisis.  Chief executive Rex Tillerson, who has led the company since 2006, is not leaving under any kind of cloud: he reaches retirement age of 65 in March, and is now looking at a second act as US president-elect Donald Trump’s secretary of state.  The question for Mr Woods — whose promotion to succeed Mr Tillerson was announced late on Wednesday — is whether he needs to do something dramatic, such as a transformational deal, to address the problems that have been gradually accumulating at the company.  If big oil groups are dinosaurs, as their critics say, Exxon’s size and engineering skills make it the apex predator: the Tyrannosaurus Rex of the industry.