To ED, its entirely useless for anything but the KA-50,
in order for your head to move sideways as if you are shaking you need a full 3d cockpit, think about it, if you are bumped to the right in your seat, You should see a another view that you never do while sitting straight (duh).
Full 3d cockpits is nothing they can just add like that, it would involve some serious rewriting of the engine, and I guess the only time we will see something of that magnitude ever happening would be the F-16 vs Mig-29 sim if it ever gets developed