I'm too having a lot of problems with the SolidWorks importer in KS3, like freezing up, not importing assemblies, missing parts, not recognizing lofts, and the like. I just ran into the surfaces issue yesterday, and I agree it's a huge problem. We often use surfaces for trim, etc., then hide them. They should not import. After import (if successful) you can hide the suspect surfaces in the Scene Tree, and perhaps even delete them.
You can also try using the "use old importer", under the advanced tab.
My workaround pending resolution of the KS3 import issues is to first import it into KS2, save it, and close it. Then use "Open With" to open it in KS3. Has worked fine so far. Of course, you're out of luck if you don't have KS2 installed.
I understand the Luxion team is working on the SW importer. FYI- I'm running Win7x64, and SW2011 SP3.0. I don't know what happens with SW2012, but I intend to find out today.
Bill G