Some might look at the release of Metal Gear Solid: Snake Eater 3D to be a cop out, but in fact Konami has been hard at work to add some great new features that were absent from the 2004 PlayStation 2 game.
Among the newest additions is the new FPS mode, which will let you look through Snake's eyes. This alone is already a pretty nifty addition, considering the 3D nature of the game, but Konami also added an over the shoulder camera, which sounds like one of the more odd camera angles. Not odd because it's not useful, but odd because it's not something that MGS relied on ever (unless you were aiming).
A big addition as well which should help those that want to ensure absolute stealth is the ability to now walk while crouching.
The new Circle Pad Pro which will be released alongside Monster Hunter 3G will also be compatible with Snake Eater 3DS.