I personally would like it if Insomniac revived the Monster Knight project that they canned many years ago as I find the entire premise of the game very intriguing. The last two Ratchet&Clank games aren't exactly stellar and I think they should put give the series some rest and do something else.
http://www.ign.com/articles/2012/09/26/insomniacs-original-ps2-game-monster-knight
http://www.ign.com/articles/2012/09/26/insomniacs-original-ps2-game-monster-knight