It used to be used by a wide variety of champions, and it's passive effect makes people feel really satisfying when you stack it 5 times. Now it feels like a Irelia only item. To other champions this is only a luxury item, also ADCs can not buy it anymore because of their level and their total hp are enough to make it useful. Their only choice now is QSS. THE ONLY CHOICE. Isn't that pretty boring?
Other champion only buys it when the game is basically already won. Back then you could buy this item both early game and late game and it was very effective against certain team combo. It had a great place.
It made you able to use your brain and really thought about what you gonna build, and that made league fun.
I sincerely hope Riot can please take a look at Wit's End's place now and consider about reverting it.
A league player since s1.