Slow shutdowns are usually there for a reason. When you ask the system to shutdown, it politely asks running processes to terminate. There are very many reasons why an individual process may not respond to a shutdown request in a short time. You would not thank your computer, for example, if it powered off with half a file written to your filing system. Hardware problems, as well as software and networking problems, can cause slow shutdowns.
If you use Google you will probably find guidance that you can use to go through the system events that take place during shutdown. There may be some clue there as to why your particular device is taking its time. If you raised a help call with Apple, they would probably ask you to provide the event log.
Yeah, but why the sudden since 10.8.X, it was never there in the past and I have never had any data loss as a result of the excellent fast shut down. Now they are telling you to wait for 2 minutes; sounds more like a lame excuse to me......