No the g-forces wont exclude humans. A proper Orion craft has a payload section and a pusher plate. The pusher plate and the payload are separated by massive shock absorbers to minimize the forces exerted on the payload.

>Two shock absorber designs were explored. The first consisted of three donut-shaped gas-filled cushions, each one meter high, looking like a stack of tires. Six-meter high aluminum pistons rose from these absorbers. This system would limit peak G forces to 3 to 4 G's. But it would be a bumpy ride for the passengers. Therefore the second design was more complex but allowed the shock absorbers to operate in synchronization in order to further even out the G-forces. This would limit peak forces to 1.5 to 2.0 G's.

1.5 -2.0 Gs is less than the 6Gs of early rockets and the 3 of the shuttle.

$200k and radiation over an area, downwind from the fallout and environmental damage noticeable across the world. We didnt stop Orion strictly because of the treaty. If it had been viable (ie worth the environmental damage) we would have negotiated it into the treaty.