I went from a stiff camber to rockered board and while the feel was different, it wasn't even close to what you describe. Once you stand up, all boards flatten out and the effective edge is in contact with the snow. It's what they do when you unweight or "overweight" them that makes them different.
But not being able to stand up because you couldn't get on edge? Ummm...that's not the board
Sounds like your weight isn't close to the center.
I agree with that too.