If we operate on the assumption that they bought the publishing rights as a package deal so they got to work on it right away once CS3 was finished, then I am pretty sure we will get it this time next year. Anything much later would be a little detrimental to the sales considering... You know.. PS5.
That is if we operate on that assumption. I do think there is a good chance it was a packaged deal, but I also think there is a chance just as big that they want to test the waters with CS3 first (from a business pov that makes more sense. So if it was a packaged deal it's either cause falcom wouldn't sell the rights other than as a package or the money they paid for each game was significantly lower in a package than a standalone).
Either way I hope the assumptions are right. I haven't finished CS3 yet, still on field exercise day 1 in chapter 3 (my speed has reduced to a crawl at this point), but I am dreading the day that the wait begins for me.