I don't think it's the last GOW. It tells about Kratos' family and about what happened BEFORE the slaughtering series of the previous games. There's also the missing part of God of War 2.5 everyone's concerned. Like everyone, I, too, want to learn how did Kratos acquire Icarus' wings, how did he climb at Gaia's back, etc...
And I hope the last GoW won't be in PS4, since everyone is against Sony and Microsoft for the restricting policies they want to build on their consoles(No BC, no Used games, etc). Right now the rumours, who are confirmed are No Backward Compatibility and No Used Games, which are confirmed from both companies, and indispensable internet connection, which was confirmed from Microsoft.
PS3 is enough for me, since it has region-free system, which it's a good bargain for everyone, independently, so I want all the GOW games to stick in this console.
He aquired the Icarus Wings in God of War 2, when he fought Icarus.