Reading through alot of the comments and ideas I have to agree with Trashman on the backstab for Rogues. It really can be done by any class and a good example would be a mage. Mage goes invisible goes behind and stabs person in the back with a dagger with great knowledge on the human antomy causing a great deal of damage.
A rogue in a sense is more like Garrett from the thief games who mainly avoids fights and sneaks around enemies disarming traps and picking locks to reach the objective and not really combat orientated. Rogue would benefit more from being a support/utility class and have viable support abilities in combat such was throwing flash bangs at enemies or even sneaking behind an enemy and tripping them over working with the fighter in a coup de grace move to kill their opponent. Rogue can also setup surprise traps used to hurt and weaken their enemies with the party luring the enemy back into those said traps.
Just my opinion on the matter and most of the posts are personal opinions though backstab in the end can be done by anyone with a weapon. Some weapons though are better at backstabbing than others.