Nose dive
I am not an A man, so hardly dare to comment on the rudder behaviour. However, many years ago, in the early days of the 757, a slow L HYD leak required the system to be switched off until required for the approach. For some reason all our aircraft required a great deal of rudder trim in the cruise (later corrected). Having such a leak and following the QRH, the result was an immediate 30 to 40 degree wing down. The aircraft, though, maintained straight and level (altitude but not wings!) flight with us hanging in our straps until the L HYD was quickly switched back on again. There was no immediate nose dive at all. This was due to a full rudder deflection. Mr B informed us later that the ratio of rudder deflection reduces with speed by 15 times due to the RUDDER RATIO which, of course, was switched off by selecting L HYD OFF.