since you moved the direction of force forward ahead the CG the pitching moment changes.
this is no different than changing the angle of the stabilizer. as airspeed increases the force applied to it would also increase. this is why you need more control input as airspeed reduces.
vectored thrust changes the direction of force as related to the CG. not the total amount of thrust produced. now airspeed, lift, drag can all be effected. Weight stays the same(although fuel is being burned, unless its electric).
If you a flight engineer, must explain why the didn't move you to the control yoke. and left you to watch the dials.