I really want to get a PS4, but not until a new God of War is announced and to be honest I don't think it will happen anytime soon, if at all. You said you only play ghosts on PS4, you should really try out battlefield 4 since its been patched up. Trade in the old games for 250, you might get more. Gamestop is having some good trade in values for old games right now. I would trade in the PS4 to be honest with you at Gamestop. You can get 397 dollars in store credit when you trade towards a xbox one, PS4 or a wii u. I traded my xbox one to get the titanfall bundle and I didn't have to pay a dime of real money for it. 650 dollars in credit can get you what you want and the games you wanted.
If you really want titanfall, get the bundle. I played the alpha and beta of it and it was a great experience. I haven't had that much fun playing online since I used to play Halo 3 with my friends in high school. I hate cod after MW2 and one of the guys behind titanfall was key in the making of MW 1 and 2. I highly recommend Batllefield 4 now that it is almost patched up. Its a blast to play 32 vs 32. Ryse is a very underrated game, a lot of people like to hate on it, but it was a lot of fun as well. Reminds of a Roman God of War without the magic powers. I can't speak on the other games you wanted to play, but I have heard good things about all of them. Ground zeroes might be better on the PS4, but things like that will be much closer down the road. The new wolfenstein game has already been confirmed 1080p and 60 frames a second on both consoles and more multi platform games will be like this later on. The PS3 went through the same thing when it first came out and history is repeating itself. It only matters I guess if you care about that stuff. While I love great graphics, gameplay is more important to me than what a game looks like.
While Gears is a way off, a Halo game is coming this year. It might be Halo 2 anniversary or Halo 5. My money is on Halo 2 and let Halo 5 cook for another year. I never got to play Halo 2 on xbox live when it was big, always played system link with all of my football friends. It was so epic playing on two tvs on all those great maps. Don't expect a kinectless sku, Kinect is too much involved in the console to get rid of.
Sorry for the wall of text, but I felt I need to say something to help you make a decision. Good luck.