I've noticed that people travel very very differently. So I would enjoy a guide that segregates users into the different reasons/ways they travel. For example some people will go to a foreign city specifically to see any ancient sites, historical museums and to people watch. Someone else might go to the exact same city but would be more interested in the food and learning the language. Same thing with safety vs adventure. Most travel sites try to fit all of this into a single "guide" which means that the typical reader probably doesn't care about half of it. So an app that allows me to select a city and then filter it's suggestions on the type of things I want to do would be much more useful than just a single long article. Then once you have this data you could rank cities as the best for historical sites, romances, nightlife, food, etc.