AFAIK, however - im not sure how far this is implemented in DCS
but most Aircraft, FBW included - would have a system in place that would artificially restrain the controls using springs or some kind of computer, so the pilot isn't just yanking a dead piece of metal around while the plane flies all over the place... (except for F-16's ofcourse, that's force sensing!)
if it's enabled in DCS, you could try it in the harrier and manually disable the artificial feel system (i believe i saw a switch for that atleast)