It's an interesting thing to speculate about.
Lyrically, I wouldn't be surprised if his next album is very much influenced by his experiences this year, of finding fame, of being away from home, of people's changing perceptions of him, the way the media have portrayed him, his coping strategies and his having to fight for his creative control, and the fan thing ( write a song about MFC Mika, go on, I dare you!). Although..that's a rather cliched way to look at a second album, so perhaps he'll steer well clear of anything like that, anything too autobiographical.
Musically, I just don't know but I hope he still mixes up the styles and does another varied album.
Actually I can't really imagine what the next album is going to be like, and that for me is the beauty of it! Same goes for his live shows. Will he go back to basics, or all-out Vegas? Well we'll see won't we.