Mages > Assassins

There's no point playing assassins; Mages are way better.

Mages deal AOE damage from a safe distance and late game they can burst down enemies too. In many cases their mechanical skill floor is much lower and their damage is much more reliable. They can also Gank lanes.

Assassins struggle to create 1 vs 1s later in team fights and rarely is a team disciplined/organized enough to close out a game even if they were ahead in the beginning.

Mages like are all way more useful from mid game to late game then an assassin.

Not to mention, assassins need to get up to your face to kill you and they are all squishy. That is just poor design; you should either be tanky and deal damage up close or squishy and deal tons of it from a distance (like mages). One silence and you are dead. Add GAs late game and you can't assassinate anyone whereas a proper Mage could have dealt sustained damage from a distance.

Plus Riot just gutted most of the assassins' burst combos.