Some 41,000 jobs have been cut and the bank has undergone a series of overhauls as former chief executive Stephen Hester sought to put it back on its financial feet.
Now, barely a fortnight in post, Mr McEwan is already working on a strategic plan for the 81% state-owned bank that will be published in February.
Loading article content
Although no details have been announced, we have a sense of Mr McEwan's approach from his 13-month tenure running RBS's retail arm.
He is prepared to make tough decisions. In May he unveiled a restructuring of the division, which involved axing about 1400 jobs over two years.
Clearly impatient with some of the more convoluted administrative processes at RBS, he is likely to pursue further simplification of RBS's systems and its still sprawling collection of businesses.
RBS could be recast as the sort of straightforward institution found in Australia, Canada and parts of Scandinavia that Mr McEwan admires.
Although there has been no indication from RBS that jobs could go, it would be surprising if further trimming of roles was not a consequence of such a move.
At RBS's retail arm, Mr McEwan has also sought to repeat tactics he used when running the retail arm of Commonwealth Bank of Australia by linking up to 40% of workers' pay, including those in back office roles, to customer service measurements.
He could roll out this bonus scheme to other parts of the bank.
RBS, even more than other UK banks, has been dogged by questions about whether it has an adequate capital cushion. Mr McEwan's strategy is likely to be scrutinised by the City for signs that he is taking steps to put this beyond question.
He will continue to be haunted by scandals from RBS's past. The Financial Conduct Authority yesterday confirmed it was investigating foreign exchange trading, which could embroil the Edinburgh bank and others. But if the Government pursues plans hitherto resisted by RBS to place some of its legacy assets in a so-called bad bank, this may actually free Mr McEwan to focus on the development of the bank.
Similarly, we will get a sense of how nimble-footed he is if the imminent publication of a review of its small business lending practices being conducted by Sir Andrew Large, can be turned to the bank's advantage.