Well historically, of course FF's bigger, it's been around almost 2 decades longer. Right now though, MH's the hot new thing, and FF's going to be lucky if it even holds even with last gen (while DQ and Pokemon are rising).
And if we add Mario, then there's other new(ish) series that are now bigger than FF (Brain Training, Animal Crossing, Wii Sports, Wii Fit, Mario Kart, etc).











