Mapping Node, Box projection, and rotation Goal

I'm trying to map a texture on a cube; 

Since my texture is not exactly fitting the correct orientation, I need to rotate it. The results are not as expected.

Setup description

I'm using the setup shown in the following pictures. I've set the projection mode to Box have the texture visible on all faces. Texture mode is set on Repeat to avoid undesired clamping (default value).
What I'm trying to achieve is to have the planks horizontal instead of vertical on the front face (rotate around X axis). The rotation is applied in a Mapping Node. 

Results 

The face I need is properly rotated, but the others get this blurry effect, which reminds me of the "Clamp" mode in OpenGL. Is this expected behavior ? How to solve this ?

**Additional note (edits) **

Both the cube and the material are simplified versions of the original problem. The meshes I have are more complex, a few thousands faces, and with complex shapes (such as switches or sockets outlets). Very few faces are not aligned with the world axes, and thus they can be ignored. The material needs to be applied on various shapes, so UV map can't be made manually. The purpose of this is to automatically create a diffuse map of each textured item, where every face with a similar direction/normal would have a similar rotation applied.

For simplificity sake, the cube seems to be a good sample
"I'm trying to map a texture to a cube"


Perhaps a simpler way of mapping a texture to a cube and have control of the orientation of the texture on each of the 6 faces is to use UV mapping?

Starting with the node setup you have already :


In the Texture Coordinate node change to UV, and the Mapping node change to Point (and reset the rotation and scale to Zero).
Drag open a new viewport and change Editor Type to UV Editor.
3D viewport > Edit Mode > select the cube, then U to open the UV Mapping menu and choose the Reset option. This will reset the UV's so that each face of the cube is mapped to the complete UV space. (Each face stacked one above the other).
3D Viewport > select the face that you would like to change the orientation of the texture.
In the UV Viewport > select the face (if it is not already highlighted in orange then use the A key to select it) and rotate it 90° with R90.




Or you can probably find the answer here http://www.blenderinsight.com/beginners-guide-to-cycles-nodes-the-procedural-way/  Under the chapter titled Object (with no reference object) :)