I'm VERY skeptical about Final Fantasy XIII. In one way, I am hoping that it'll breathe life into the genre and make it less stale. On the other hand, I look at the teenage melodrama trailer and I seriously wonder if I'm no longer the target demographic anymore. The convoluted teen melodramas that were FF7 and FF8 were fun when I was young but so was freakin nu metal. Doesn't mean anything. Final Fantasy and most jrpgs haven't grown up and cater mainly to pre-teens and teens and hardcore grown men fanboys who still seriously believe that FF7 had a masterpiece of a story even though it was pretty just pop corn entertainment with some pretention. Or it could just be that they've been fooled by the nostalgia illusion (which is probably more likely).
That said, Final Fantasy deserves the success they had because they were willing to take the risks necessary to bring attention to the genre while companies like ATLUS stubbornly cater to their already-converted echo chamber fanbase.