The often posited post-war preference for a defensive war in mid-'43 relies on the assumption that the Germans retained an operational superiority they rather manifestly did not have by mid-'43. If the Germans withdraw to the Panther-Wotan Line months ahead of time, then that means the Soviets have that many additional more months to crack it, not to mention additional manpower resources from both lack of casualties and recovery of territory as well as the ability to begin restoration of Eastern Ukraines mines and industries further ahead of time. That's not going to lead to the Soviet advance slowing or the Axis minor allies being in the war longer...
In any case, the idea that there was a widespread preference for a defensive stand amongst the German generals in mid-'43 is ahistoric. The primary debate amongst them even at the time was not whether to defend or attack, but where to attack.