There are some features that Apple could add to make better the find my iphone
1- Locate your phone every X minutes, this way if you lost your iphone and they remove the sim or turn off wifi you could see the last location.
2- A security feature where the first owner of the iphone ( the first one to connect it to itunes or the first one to turn it on ) could store a find me account that it could only be disabled by the same people. This way when some one insert a new sim or they restore the iphone you could still find your iphone. Only the first owner could change this information, or delete this information.
3- Apple could also help owners locate their stolen iphones, they know where they are because an iphone constantly sends information to Apple servers when they buy apps, connect the iphone to itunes, etc.
4- Send an email with the last location or locations of your iphone, what is the reason to receive a mail saying that your iphone was located and when you access to view the location there is no information because they have deleted the icloud account.
Apple could help end the theft or lost iphones but they don't want because I am sure that is also a big business for them. When you lost your iphone you go and buy another one. Apple gain a lot of money from this.