Assassins

Need to do more damage late game.

They really do, or their role in teamfights becomes watered down and blends with that of a fighter.

But this has to come at the expense of a weaker laning phase. When an assassin has an easy lane in most match-ups and also has the ability to make clean late game picks, they become unbearably frustrating to play against. Effectively, if you are the lane fighting against them, all you can do is mitigate the assault and make yourself a less favorable target. If the enemy plays well you cannot prevent their mid game spike, and it is this feeling of inevitable demise with no recourse that makes these champions so anti-fun.