As others have said on here, this is another police PR exercise of questionable intent.
If it wasn't, they'd have just got on with it, instead of taking half of London's press and TV cameras with them.
I don't know whether Soho's any more dangerous for the average person than it's been before, but I suspect that crime rates on a per capita basis are pretty low. I worked in W1 for donkeys years, and the tarts, restaurants, porno shops etc all got along OK and pretty much left each other alone and quietly got on with it. Less quiet of course, has been the development of the Rupert Street/Old Compton Street area as a gay hangout, and the caterwauling that goes on at chucking out time has to be heard to be believed.