This patch makes the Persian Hall and Ishtar Gate unbuildable.
0 A.D.'s interpretation of the Kardakes is rather problematic; see this forum thread.
Only after his defeat by Alexander the Great at the Battle of the Issus (333 BC), Darius III sent for a new army. At the Battle of Gaugamela (331 BC), which marked the end of the Achaemenid Empire, about 15 Indian elephants (Arrian Anabasis 3.8.6) participated. This is the one and only known case for the Persian use of war elephants. Apparently they're a novelty. War elephants are not mentioned by Herodotus (covering history up to c. 480 BC), nor by Xenophon (describing the situation c. 400 BC).
The hall actor itself is loosely based on the Gate of All Nations in Persepolis. However, 0 A.D.'s version has entrances only on two sides; the most important one, one the south, facing Darius's Apadana, is missing.
The famous Ishtar Gate of Babylon is Neo-Babylonian, i.e. predating the Achaemenids. Allowing pers to build it is anachronistic, akin to ptol building the Great Pyramid at Giza, or brit building Stonehenge.
Taking everything into account, it's probably best to disable these historically inaccurate assets for now.