Peter III was a fool and for that he paid the price but he was the first who had a bit different approach to the problem how to move Russia geographically westward to the seas.
Instead of potential gain of eastern Prussia iwhen he spared Frederick II he planned future war against Denmark for the stated duchy. The question is; no matter if he or some successor of his realizes the conquest, you have Russia in the control of the Baltic with free access to Atlantic and separating Denmark from german states.
What would be the consequences, only what I can think of is that Russia would build massive fortifications and keep mighty garrison in case of any war with german states since they would first strike there.
Instead of potential gain of eastern Prussia iwhen he spared Frederick II he planned future war against Denmark for the stated duchy. The question is; no matter if he or some successor of his realizes the conquest, you have Russia in the control of the Baltic with free access to Atlantic and separating Denmark from german states.
What would be the consequences, only what I can think of is that Russia would build massive fortifications and keep mighty garrison in case of any war with german states since they would first strike there.