Heath Ledger's Joker was a very unique interpretation, and the actor's untimely death added to the hype.

What used to make Lex interesting was that he was someone who believed Superboy wronged him, and had a lifelong grudge. That went out the window in subsequent reboots of the DC universe. Lex has been more like an evil Donald Trump in more recent incarnations.

One reason behind the Spidey movie reboot is if the studio doesn't crank out a movie in a certain time frame, the rights lapse. Sony is going to milk the webhead for all they can get, before letting Disney get him back.

If they want a compelling villain we haven't seen in a Supes movie before, and someone Superman can fight toe to toe, there's only one way to go, and that's Darkseid. There probably saving him for the Justice League flick though.