Voice from the center is by design. When you talk to a person, where does their voice come from, straight ahead or out from the sides ? Barely hearing anything from the rear is also by design. I think anything from the rear during a "normal" scene will be rather discrete. It's really only used noticeably during some scenes, such as something moving and going past you. Try Black Hawk Down, for example, and the helicopters will start quietly in the rears, get louder in the rears (as if they're coming towards you), then transition to the fronts. Other scenes, such as a door closing, can be done only through the right rear or left rear and can sometimes cause you to actually turn your head.
Totally agree. THAT is what surround sound is for. Those pops, bumps, and creaks when watching a spooky movie. Even the craptacular Paranormal Activity series of movies made excellent use of the surround channels that makes the wife/GF cling to your arm. There have been a number of times where I've gotten up to peek out the window to check if there REALLY was a thunderstorm outside. LOL Saving Private Ryan is another great example of effective use of surround sound to convey the sounds/experience of war.