The safety issue in NO is the same as with any other place you may want to visit. Be aware of what is going on around you at all times.
The fact that someone visited NO before, has zero bearing on what is going on today, or when you get there. The NO police force actually has 500 LESS officers now than they did a few years back.
There are crimes in the French Quarter. In fact, Bourbon street has more crimes committed in it's short length than any other street in NO. Most of those crimes are petty offenses, like pick-pockets, theft, or simple assault. There have been three murders in the French Quarter so far this year.
Basically all you have to do is search the NO news sources(newspapers and TV stations) for current 2014 news and you can educate yourself. As long as you use a little common sense and remain aware of what is going on so that you can avoid bad encounters, you should be fine.