Nasus is unhealthy for the game

Seriously, his kit is completely unhealthy. You either end the game at 30 minutes or he becomes unkillable. This forces that playstyle on the ENTIRE team. (No other champion does that). This simply bad design and nobody else seems to chastise Riot for their terrible design choices.

He can permaslow and I know that Nasus was created by Riot to be built with items that do damage but everyone just spams defensive items on him because of his absurd stacking Q.

The simple thing that can be done to make him more skillful is make his Q damage that you can actually defend against. Create an item that reduces true damage or change his Q to magic or attack damage.

It is simply not fair to be winning a game up to a point where Nasus can pretty much kill everyone while being unkillable himself. Even isn't this badly designed, he has a stacking mechanic but he is squishy so you can counter him.

can be killed in the laning phase, rather then just sitting under tower and farming like Nasus does because his health and resistances are so high.

I never understood why Riot buffed Nasus a few months ago, he's so easy to play and an entry level champ, he never needed it.