Actually it is.KarinsDad said:What a Wall of Force blocks is specific to spells, breath weapons, and creatures. Nothing more, nothing less. It is not solid.
PHB pg 299:
"The caster can form the wall into a flat vertical plane whose area is up to one 10-foot square per level. The wall must be continuous and unbroken when formed. If its surface is broken by any object or creature, the spell fails."
If it is not solid, as you suggest, then it could be formed around creatures or objects. The spell states the opposite. The wall is a continuous, unbroken plane when formed. It does not change afterwards. Since it is a solid wall it provides total cover against attacks. The only thing that actually passes through the wall are gaze attacks, as stipulated by the spell itself.