They are almost assured to be different stories, hence what I mean by different. Also, my argument isn't about the Joker being developed (since TDK showed you can have an origins-less Joker). My point was that the inclusion of Joker is incoherent in relation to the rest of the plot points/parts that make up Batman v. Superman. It makes no sense for what the plot wants to accomplish (which sounds like your basic, fight then make-up and bind together against a common enemy story a la the first half of the Avengers).
The problem with assuming that Lex would want to get Superman out of the way similarly to WF, is that how do you do so without Kryptonite? (seeing as how Superman in WF was in actual danger of dying). The Joker is nowhere near physically inclined enough to take on Superman so it'd be ridiculous to write a battle without an equalizing force similar to WF's. Furthermore, if the Joker doesn't need to be developed any more than Luthor...then you're essentially asking for a partial origin story...I mean, this is the audience's first time at seeing Snyder's Lex Luthor, so we still have to get to know his character, his personality, his motivations etc.
