I am making a wall collapse by dividing a brush into gibs and making them all func_physboxes. The problem is when I use the output enable motion, the wall doesn't exactly collapse because it's too tight with the wall or something. The enable motion still enables motion though, I can pick up the gibs and everything, but it won't automatically fall. I tried using an env_explosion but it isn't strong enough. What else can I do?

Try an env_physexplosion. Trigger it 0.05 second after or so, to make sure the boxes are affected.

Or use the output 'Break' for the func_physboxes