For what I noticed almost half of the times long passages end up where the CPU wants them to end, not where you directed them

At least in the past, that was an issue. The reason was probably the stupid scripts. However, it's possible that if both passer and receiver have high teamwork, there are better chances that the pass is successful. Response might also play a part in it since a player with low response is less reactive and possibly takes more time to get towards the ball.

Long passes never worked for me in the old engines, because the passes were always too high and slow so the opposition always got in position to intercept them, that and your player always had to be directly under the ball to control it on their chest. And if it bounced then you could never reach it because the game couldn’t really recreate backspin too well. However in the newer engine they are good, because you have the Low Lofted Pass ability which lets you play those beautiful long passes out to the wing, and with more animations for controlling the ball your player can easily bring the ball down if it’s at knee height or higher. In the older engine it was only really useful for crossing the ball IMO, now it’s a good stat to have for midfielders and if you have a player like Pirlo you can easily create chances just from playing balls over the top from open play.