The reason the AP Mages are gettinga rewirk cuz they all do that same thing basically with different looking spells. They all have AOE, they all do massive damage and that's about it to their uniqueness. All those assassins you listed fill a niche role. Katarina plays alot different from Shaco, Talon and Akali, vice versa. Akali has resets and can assassinate but rather slowly, Katarina has resets but, doesnt really have 1v1 damage but, a shit ton of aoe, Talon has insane 1v1 damage and AOE but, after his intial burst he has nothing, Shaco is just a fucking troll and fucks with your head. There are clear differences in their gameplay meanwhile whats teh difference between a Brand and Lux, yeah their spells have different ranges but, beyond that in teamfights they play the same. You stay behind your tanks and just deal massive damage.