I don’t much like the ‘green goo’ tsunami that insta-kills the orcs. I do think the Extended Edition improved it slightly as we see more of Aragorn and Gimli on the battlefield killing orcs including Gothmog, so they are still participating in the victory even after the Dead arrived.
I think the only way to accomplish it would be to have the Army of the dead arrive on the boats and join the battle but delete the shot of the green goo swarming over the Oliphaunt (Day Z style) and then flooding the streets of Gondor - really just 3 seconds of footage to cut. Replace it with some slo-mo battle footage of regular men fighting and perhaps a short voiceover by Gandalf “the turn of the tide…” to imply time passing and the battle being won, then segue into the aftermath of the battlefield.
ps. if you’re going to make an edit then also tweak Denethor’s burning man marathon run, that’s far sillier than the Army of the Dead!