Obviously, it's way too early to talk about what this album will really be, but I figured it'd be an interesting discussion topic.
The way I see it:
Hybrid Theory was this first nu-metal magical album that launched them into the mainstream.
Meteora was intended to be a continuation of that magic and was meant to see if LP still had what it took to do it again.
Minutes To Midnight was LP attempting to step out of their comfort zone and create songs that didn't have to be restrained by the "LP" sound.
A Thousand Suns was LP going far out into a concept album, and trying to venture into as many different genres as they could, while writing some almost psychedelic material and totally stepping out of their comfort zone.
Living Things was LP going back to some of their past familiar territory while still trying some new things, but mainly striving to fuse all of their previous records together into one cohesive, new sound.
Now, my question is, what do you think will be the main concept/theme of their next album?