I may not have thought this all through. First point is sound though.
yes
in an attempt to be serious -
first, reduce crime.
a fair chunk of crime is poverty related. decent housing and a social security system that works would reduce crime.
another big chunk is drugs related. 'prohibition' doesn't work. recreational drug use should be regulated like recreational drinking, addictive / problem drug use should be health not crime.
and police should not be trying to deal with the failings of the mental health system. yes, there are extreme cases where someone with mental health problems needs the public or themselves to be protected, but in general, a copper with a taser and handcuffs all over the place turning up to a mental health crisis is probably going to aggravate more situations than they calm (i have a friend who ended up inside for that reason.)
second, rebuild democracy and local services
most councils (and i include the current london boroughs) are too big and too remote from communities. and too many councillors are careerists, either using it as a stepping stone to jobs in think tanks, as special advisers to national politicians, or for the most ambitious, to becoming an MP; or alternatively as a property developer / planning consultant.
and this in turn means people care and vote less about councils.
although you need county level councils to do the more strategic stuff and take some of the powers away from a whitehall machine that was built to run an empire and now tries to justify its existence by treating councils as if they are colonies.
and of course get rid of the quangos and privatised / quasi privatised things like academies, health trusts and all that sort of shit and give most if not all of it (back) to the appropriate level councils rather than whitehall.
there is an argument for having some things done at neighbourhood / (civil) parish level, even in london - the SDP (or alliance or SLD or whatever it was at the time) did try moving some decisions to council ward / neighbourhood level some time in the late 80s or early 90s, but panicked when the NF or BNP got one councillor elected, as if that ward had elected a second far right councillor out of 3 in that patch, it could have got nasty.
which brings us on to police accountability. and how big a police force for london should be. criminal activity doesn't respect council boundaries, and even the current london boroughs would probably be too small (and westminster would have some huge peaks of work for big events, although this could partly be reduced by abolishing the monarchy.)
the old
police authorities had a mix of local council appointed members, magistrates and independent members (although if they had to be approved by the other authority members and the home office, i'm not sure just how independent they were.) especially in larger / merged police force areas, they were too remote. a single PCC seems to even more remote.
as for the operational end of it, the management, recruitment, training and so on, someone else can do that. it's bed time here...