Is your 12-35 soft?
As already said general softness is mostly caused by focusing problems that are more common on a dslr than a mirrorless camera with cdaf.
Softness can happen though, as a result of imperfections in the lens elements.
What is more common is that one of the lens elements isn't positioned perfectly resulting in what is called "decentering": the images are then softer on one side or in one corner than on the opposite side or corner. Very slight differences are certainly within manufacturing tolerances but when one side or corner is clearly blurred the lens needs to be repaired. To detect this problem: take a picture, then take the picture again with the camera upside down. Both images should be equally sharp in the corresponding parts of the image. In a bad lens the differences will be immediately obvious.
Slowly learning to use the Olympus OM-D E-M5.
Public pictures at http://debra.zenfolio.com/.