It's like
@Matt10 said earlier:
I downloaded Klash's 2020 tactics and yes, they make a positive difference, there's no doubt. But does it stop the AI passing back to the CB and then hitting a perfect 100-yard pass to the striker, who always perfectly chests it down, turns and runs at goal? It factually doesn't (I played four games in a row, and Leicester, West Ham, Man United and Arsenal all did it multiple times per game).
Just one example, of many (like the AI getting away with murderous fouls, players sprinting back to their formation-screen position because "transition play" just isn't part of the code, etc. etc. etc.) - it's the core of the code.
So much so, I played PES5 earlier today and lo-and-behold, I spotted a few familiar things and laughed out loud. AI long balls forward when you cut off a single passing lane, for example. This stuff has been around for a long old time.
But at least there's no "turn-shoot" goals, and there are (somewhat incredibly) more off-target, less-perfectly-powered passes. Constant AI pressing at least makes it feel like there's some transition. And some of the tactical options I swear are better integrated, and more powerful...
That's not to mention the defensive options (I forgot there were three defensive line options). Or the "original" version of "team spirit"...