I believe they said they'd appear at most, if not all, of the major gaming conventions. But I haven't heard a thing about whether or not they will have character reveals at all of them. They might as well be focusing on other aspects at the other dates, reveal levels or minions or game modes or something.
At the Gamescom panel (Video is on Youtube but I can't find it), Yes he said they will reveal stuff whenever there's an event. Then he acknowledged TGS,
Also some guy asked him if there's a FF character. Omar made an interesting reply to imply there is. He said something like "we haven't announced a FF character yet". Maybe it was a poor choice of words, I hope not.
he said maybe stay tuned --- http://www.facebook.com/Timesplitters4PLZ <<<<<join this on facebook and maybe there wil come a timesplitters 4!!!