Johnson didn't have any positive policies (other than the bizarre magic-Routemaster promise, which can be translated as either "let's divert a few million pounds from boring things like housing and education into designing a cool-looking retro bus" or "let's play a game: you pretend you're an idiot and I'll entertain you"), but got elected on (a) his raffish, loveable-buffoon image, and (b) dog-whistles to reactionary resentment (too hard/expensive to drive into London, too many unruly coloured youths/scary Muslims, "It's political correctness gone mad!"). In fact, he had expert coaching in the art of dog-whistle politics, having been managed by Lynton Crosby, who helped keep a right-wing government in power in Australia for 11 years, tapping into much the same reactionary sentiments and unspoken but popularly accepted bigotries.
It's overwhelmingly likely that the next four or so years won't be an era of innovative initiatives in London. Don't expect things like the Paris bicycle hire scheme, bold new green initiatives, pioneering public transport policy (something Ken Livingstone was actually really good at) or forward-looking visions for a metropolis at the centre of global culture. We can almost certainly expect the congestion charge to be abolished or "rationalised" to the point where nobody has to actually pay it (except perhaps for those pesky cyclists who get in everyone's way), and the axe to fall on Ken Livingstone's public-transport expansion programmes (you can forget about the city tram or the East London Overground reaching Clapham Junction), and quite possibly on Transport For London itself, abolishing this Inefficient Socialist Bureaucracy and flogging off individual tube lines to bus companies. The daily commute won't get any less slow or cramped, though at least those who own cars will have the option to drive. Also, if Crosby's previous client is anything to go by, expect the ugly politics of division and the "culture war" to come out, to see Johnson publicly beating up on cosmopolitan elites and "un-British" foreigners, to mass applause from the Daily Mail readers who voted for him. Certainly, Ken's celebrations of multiculturalism will be replaced by fields of Union Jacks, with Land Of Hope And Glory blaring through the tannoy. But the good side is that it'll be really easy to find parking at the Olympics.
The gist of this is that it now looks like, over the next few years, London will become an even less attractive place to live, even more paranoid and mean and self-absorbed, a backward-looking place whose glories are all in the past, with Boris Johnson's rhetorical Routemasters. And in four years' time, Londoners will look over their dirty, traffic-choked city and Ken Livingstone's reign will look like a golden age in comparison.