Alright, this is my definite idea of what's happening. I got the demo from Steam, played two Barcelona x Arsenal, and then played two Barcelona x Arsenal in PES2016. At least for the demo...
- PES2017 is better AI wise. No doubt. I had always over 60% possession but failed to score (0-1 and 0-1). In PES2016 I had an average 50% and scored 7 goals (3-0 and 4-0), mostly from counter attacks (at least the first goals). They just defend better and make fewer mistakes. Attacking is simiar, but PES2017 still takes the edge. More incisive and dangerous. Still pingpong passing though.
- PES2017 might be better tactics wise, but the difference is not as big as I expected. Not a deal breaker.
- As for the rest of the gameplay, goalkeepers are much, much better, speed of the game is nice, passes and animations are more diverse and better (but I do prefer the Weighted Pass animation of PES2016, they all look like pros in PES2017). Improvements exist, just not as big as they should be. Oh, and Speed seems to have greater importance this year.
- PES2017's graphics, overall, are just a tad worse. Crowds I didn't even notice, faces are better, grass is much worse, the overall feel is worse, too much motion blur and bloom. I like it though, even if it isn't worth €50.
In summary, it is better, and PS4 surely has a great game, but the bullshit they pulled on PC gamers is not excusable. I won't buy the game (for now). I'll miss the keepers and less mechanical sliding tackles, but having less broken stats (that Body Control, oh Jesus...), better overall graphics, a patched game from the start and saving €50 is good enough for me.