system
A chat on subreddit /r/NoStupidQuestions
human
&gt; I'm still waiting for old malls to be converted

I'm all for this idea. You can solve a myriad of problems at once like this. 

Keep the mall. The stores, parking, and food courts all stay. The BIG BOX stores (Sears/JcPenny) get torn down, and apartments go up in their place.

Apartments are now next door to retail. Apartments are in a good location (malls were built near infrastructure (i.e. highways)). Convert one of the end caps into a grocery store. (people can walk to the grocery.) Put a couple of Public offices in vacant office space; social security office, police station or DMV. 

You can put a whole bunch of people (about 150+ apartments per mid-rise building) in an old dead mall.

Zoning laws are not going to be your friend though. Neither is the local infrastructure. (Can the schools handle the additional population?)
gpt
Others have pointed out that this idea is a logistics nightmare.  Plumbing alone just plain won't work without gutting the place anyway.