Topping Metal Gear Solid Series will be tough. Nobody in history has beaten Kojima's story telling abilities.
The story in MGS is ridiculous at best.
Final Fantasy has always had great story lines, but the gameplay up until FF7 was generic and somewhat bland.
Then came the Guardian Force system in FF8, and the Ability Crystals in FF9, and then Sphere-Grid level system in FF10, then the License System (Or what I call Sphere Grid 2.0 minus spheres) in FFXII, and now FF13 is going to have a revolutionary combat system.
I just hope there's some yaoi fanservice or some animal-based party members like FF12 lacked.
The summoning system looks great too, especially considering the Shiva Sisters and of course Odin
Did you miss the Viera in FFXII? Not to mention the moogles <3