Both Metal Gear Solid and Final Fantasy have been seeing diminishing returns in recent years. They were blockbuster new products in the PSX era (and, yes because FFVII was a significantly different experience from earlier RPGs, it was new in a way that later Final Fantasy games were not), and the luster of that helped them sell quite well in the PS2 era. But neither of their PS3 incarnations have yet been proven to be anything but slight modifications on their previous incarnations, they're unlikely to spark the popular imagination in a way which will sell the PS3 on a massive scale. They'll probably both be good games (well, at least MGS4 will. who knows with square these days...), but they probably won't be the savior of the system that some people expect. This same effect can be seen on Nintendo consoles in the drop off in sales from Super Mario 64 -> Super Mario Sunshine. It seems possible that Galaxy will reverse trend, but I'll reserve judgment on that for the time being.
I, for one, would welcome the people behind those games working on new IPs and new types of games as their main focus.







