To me, the mad scientist version of Lex Luthor has almost no value in the modern day comics, as the Post-Crisis version of the character has almost hilariously outshined him in every way. A lame, cliche mad scientist just doesn't seem interesting or intimidating in the slightest, and those traits are needed for an arch foe, let alone when it's someone like Lex against someone like Superman. Tycoon Lex's money allows him to have others build things for him, thus still allowing him to "Create" things to fight Superman. However, by doing it this way, it's not nearly as cliche and trite as the old days, which was basically "Taste my newest death ray, Suepahman!!! Hahahaha!" As trite as an evil business man might seem, that is a FAR more interesting role for Luthor considering that corrupt corporate tycoons making shady business deals that inadvertently shape the Earth is actually something relevant. The polymath Luthor was only created to placate Silver Age fanboys, and any interesting mad scientist storyline (eugenics, gene splicing) done to its fullest potential, and not just some comic book trope storyline, would be inappropriate for Luthor's character. Any and all mad scientist stories should just be used for a new version of Ultra Humanite.