If we really are talking about level flight in still air, then acceleration at idle power is extremely unlikely. We would require an aircraft in which the thrust from the idling engines exceedes the drag of the entire aircraft in level flight.
But if we have all of this thrust at idle, then other than for take-off, why should we ever want to throttle up to any significantly higher thrust level. This is what Not So Fantastic means when he says that the aircraft would need to be extremely overpowered.
He is also correct in saying that such an aircraft would be very difficult to land. Extending the landing gear and flaps would increase drag, which might be enough to decelerate to landing speed. But how would you achieve the initial deceleration to Vfo and Vlo?
It is quite possible that an idling jet engine might produce more thrust than drag. This would cause the engine to accelerate if it were not attached to the aircraft. But in level flight idling jet engines are never reallistically going to create thrust greater than the total drag of the aircraft to which they are attached.
If they do then they are attached to the wrong aircraft!!!