Maybe I'm not thinking clearly here, or maybe I didn't explain it very well.
The wall won't stop normal objects or creatures. Won't stop Golems or go-karts, arrows or aardvarks.
What it will block is Force effects and Ghost Touch items.
So anyone with Mage Armor up, or wearing Bracers of Armor (which uses the same spell) will have a problem. The wall doesn't affect the Material plane, the Force effects and Ghost touch items affect things on the Ethereal, where the wall is.
Now, granted, the wall won't be anchored to anything relative to the Material plane, and that may be the downfall of the idea. But until something comes along with enough force to move it...