The Assassin update should focus on making assassins feel atleast decent to play against.
With distinct gameplay and reason to be picked being secondary concerns. Assassins dont tend felt good to play against unless you are bashing their heads in and that isnt the way a class in League of Legends should exist. Assassins really do have less counterplay than most other classes. In most cases: If a tank is causing problems building pen tends to work, you can easily catch out a mage with multiple people if one of them is snowballing, Marksman can be killed quickly and tend to be vulnerable when alone, Fighters can be peeled away easily, and if a support is whats decimating your team there is an issue or that support is a god. Most assassins are so old that meaningful counterplay the just isnt there because designs didnt include that much counterplay at the time. Of the 17 champions most players consider to be assassins, 10 assassins were released in season 1 or earlier. These champions are old and need the some modern designs, which hopefully mean more counterplay to some for some of these champs who just were not designed with counterplay in mind