There's not gonna be any more Ratcet games on PS3, thats for sure.
Well, the PS4 is planned to be released on this year's holidays, from previous experiences, that's more than enough time to make a full fledged R&C game.
Well, looking at the PS4 games already announced, alot of them are going to be released on PS3 as well. Here's hoping the next R&C comes out on both. Otherwise I'll be waiting for the PS4 to be alot cheaper and all the bugs solved before I buy one……