The Theory: Yondaime Will be summoned back In the future
Remember when Orochimaru was fightin Shodaime? When he used Edo Tesei? Well he managed to summon 2 coffins and he couldn't summon the third.
This means that Yondaime could still be summoned because it wasn't sealed when Sarutobi sealed the other 2 hokages.
We also know that Sasuke_Kun Absorbed Orochimaru and all his techniques.
So there's a small chance that Sasuke_Kun would summon Yondaime.
Well there's alot of reasons but the main one i Think Is maybe to help naruto learn Hiraishin
Or to help him in battle maybe against Someone like pein.
What are you're thoughts