I looked up the original shooting script. Found both the one Donner used, so really the true original. But also Lester's modified version which is very interesting. The confrontation is different than what was rewritten.
The idea was that the Fortress would be like a house of mirrors. That they would all be hiding behind crystals but also all of them using their reflections as a trick to appear other places. What ended up on screen does not really convey that at all. This does explain the original thinking.
I could see why some see Donner's confrontation as anticlimactic. But I think Lester's additions were unnecessary. The Battle in Metropolis is the big show down. Donner's gives Zod the false self confidence that Superman really has resigned himself to defeat. After his leaving Metropolis. When really it was all a setup to depower them.