I would say...
Force effects are all selectively permiable membranes of force that allow normal atmosphere through but nothing else. Thus, nitrogen, oxygen, small amounts of water vapor, carbon dioxide, etc. could all pass through. Breath weapons, inhalents, gasses, people, cannot because they are not normal atmosphere.
The escape artist thing I would rule is like the myths of people pushing through glass through slow, patient pressure. I would make it take at least 10 minutes and keep the DC at 120.
Walls of force are not designed to be offensive, nor should such a use be permitted. My players have tried the "sideways wall" to be a 2D blade. NO. They considered the suffocation effect. NO. The entire concept of using a cage instead of blasting them with a Delayed Blast Fireball is that in theory you want to keep them unharmed. I feel that the original maker of the Forcecage spell took that into accound and made atmosphere pass through it.
JMHO.
DC