By the time the new hero Superman encountered Brainiac early in his career, the Kryptonian machine monster had digitized and assimilated hundreds of worlds throughout the galaxy, dismantling the physical copies (including Krypton itself – Brainiac hid the threat to the planet until the last minute, defying his creator and escaping with the only record of the destroyed world, a sort of virtual bottled Kandor).

If Brainiac arrives at Earth with that digital Kandor, including General Zod as a digital record that can be physically reconstituted, Zod could be introduced in the first movie and set up a second.

The Brainiac animated episode also had a ruthless corporate Lex Luthor using all his megomaniacal powers to try to get his hands on Brainiac\’s technologies. That story thread paid off ten years later in the second to last JLU episode, bringing together Darkseid and Brainiac as an ultimate threat.