There’s a new scene in the Ultimate Edition that clarifies that Batman has sent him to Arkham, so we might even se him at play in Suicide Squad in August.
There’s a longer scene, before the controversial Capitol Building bombing, where Finch starts to piece together how Luthor is the one pulling her strings.
These would have been GREAT additions to the theatrical cut, so Lex’s convoluted plot would have made more sense, overall.
Lex Luthor will get more opportunities in the DC Extended Universe.