From a technical standpoint, Shadow Fall. 1080p, material based rendering, tesselation (absent on SS), good AA. Ryse could get the spot, but the 900p presentation hampers image clarity. Second Son looks gorgeous, specially for an open world game, but it lacks some of the tesselated goodness of SF. Metro LL Redux is closer to SF.
The rest of the games distant. Driveclub and FH2 looks good, but both have their shortcomings in specific areas. Ryse has the best character models and animations. Shadow Fall has the best lightning, tesselation and overall visuals. Metro has the best textures.
It's interesting to note that none of them are really "next-gen". Most games launching now use last gen technics. Some use a mix of last and new gen techs (Shadow Fall, Shadow of Mordor, Ryse, Forza 5 and Horizon 2, Driveclub, Second Son, etc), but they have their shorcomings, old assets here and there and so on.
Now, people saying Far Cry 4 are out of their mind. The game isn't nowhere near close to next gen and only uses last gen tech. Good game of course, but here we are discussing technology.
