in the future the place will be called The Saxon Palace with the Tomb of the Unknown Soldier. Do you see the difference?
No one is going to call the place with this most absurd name as you propose. The Saxom Palace will be Saxon Palace and the surviving part will still be the Tomb of the Unknown Soldier.
The Saxon Palace is an important part of national heritage in Warsaw. It should be rebuilt and will be rebuilt despite of what the rednecks of Zielona Góra and other regions of the country may think of it. The Palace may eventually take a different architectural shape than before 1939 as has been the case with the Royal Castle in Warsaw which was rebuilt in an older shape than that from before the WW II.
I like watching the ceremonies there if I am walking by.
The ceremonies take place on what was once the cour d'honneur
of the Palace. A re-built Palace will not take over any part of the place they are held on.