Do you prefer pacey player having the same pace as slower player? If so, I don't think PES 2018 will be your game. However PES 2017 is more "balanced" in that aspect. I want to be punished if I don't time my tackles right especially if it's against a pacey player. However, I don't want to be punished by the "script/code" deciding it for me. I don't have much issue with PES 2018 sliding tackle however the normal tackles needs more work in terms of controlling and timing the tackles. So many times due to the bug in the coding, when I hold the tackle button or double tap, the defender faces the wrong direction and let's the attacker through. It can easily be rectified with more control over the tackling and less automation. That's what makes skills and pacey players op when you don't give the defenders more control over normal tackling. However knowing PES and it's fan base, PES will rather introduce "catch-up" bug and players like Bale will be useless again instead of giving more control to normal tackling/pressing/jockeying.
Can you post examples of the script/code allegedly deciding things for you?
I'm going to be completely honest and say I have no idea, at all, as to what you are talking about regards automation. It sounds like you play with all your focus on the ball carrier when defending and always control the closest man to the ball and look to make the perfect tackle as soon as possible. This game will punish you if you put all your eggs in one basket like that. It will certainly cause many a frustration.
Is the standing tackle perfect? No, but it isn't completely automated either, nor is outcome overly scripted or coded.
Defending is not automated in this game. It is no more automated than defending in a 1v1 situation in real life.
In my experience, this game actually demands that you look to defend against your opposition with your team, not just the dude you have under your control. It demands that you marshall your defence. It demands some conservatism. It demands that you concede some ground and sometimes requires you to defend "passively"
That is how defending works in the real sport, regardless of the level. The teams which defend best are the teams which defend as a unit, not those with individuals displaying laser precision in tackling in 1v1 situations. If you stuck Giorgio Chiellini in a situation where he is out wide and, I dunno, fucking Christie Elliott has him in isolation then if Chiellini just looks to pressure him recklessly, looking for a laser precision standing tackle then I guarantee you Partick Thistle's Christie Elliott would beat him more than you think he would. Yep, Christie Elliott.
I mention Chiellini and then I think of Juventus and the Italian national side and how what is now a broken up defensive trio were considered the absolute best defensive unit of recent times. I would tend to agree, but did you (or others) watch the matches in which commentators, analysts and fans alike were reaching that conclusion? It wasn't because they were all doing laser precision standing tackles in 1v1 situations, early and all over the pitch. Nah, a LOT of their defending, their world class defending, was done as a unit and also very deep or in last ditch tackle situations. It sometimes wasn't Chiellini who took the ball off the ball carrier, but his tracking work combined with the rest of the unit seeing an attack break down. This beta has allowed me to approach defending with a similar mindset that even the standing tackle not being perfect matters very very little.
Defending can be ugly in this game, but defending can be awfully ugly and last ditch in real life too. In real life, when it comes off at the highest level, it can even be called World Class.
While not perfect, or finished (which it isn't) I love the defending in this game.