The long stretch of temperate weather, major arrests of gang leaders sparking turf wars, and changes to police tactics are mostly responsible. Of course other social and political issues are always there pushing things along too.
Still the per capita murder rate doesn't crack the top 10 in the country even with the recent increase. If you want to see a place with a truly shocking murder rate New Orleans would be where to go where, with all respect to the General, troops did not solve the murder problem.
To really tackle the problem the city needs more cops, decriminalization of drugs, and to address the social problems inside the black community that contribute heavily.
Closing/combining low enrollment schools is inevitable, even the CTU recognizes that. Population loss from certain areas of the city combined with aging physical plants in some cases are major contributors. Increasingly parents also want the option of charter schools...for better or worse....so most new/replacement schools will probably be of that type.
The city needs more cops but the city needs to get it's labor deals with CPD done before that can happen. Retirements have greatly outstripped new officers being hired into the force.