Great discussion.
Now what do you say when the question pops up in an interview?
If you have asymmetric thrust, you will have to counter with rudder to stop the angular motion around the vertical axis going trough the CG.
Then if you want to fly in a straight line you will have to add up (after steady state condition has been achieved) all components of all forces involved in the horizontal plane.
If this sum in not zero, no way you will fly in a straight line.
How do you make this sum Zero?
The only thing you can do is to change the position of the CG and start all over again.
However, you may not be able to change the CG sufficiently enough to achieve the goal of straight flight.
Now is this a nutshell answer or not ?
Since it is not guaranteed that the CG will be in the longitudinal axis I see why Concorde trims the fuel in both directions lat and long.
Since in steady state and straight flight the only force on the slip ball is gravity, the ball can be anywhere depending on the amount of bank you need to set all equations to zero.
With straight line I mean straight direction, the plane could still be climbing or decending in a curved line.