I just played Katarina for the first time.
The enemy team didn't follow that rule. But I was too inexperienced with Katarina to play her to perfection and take kills while using Shunpo 5 times a second. So I just went Abyssal/Rylai's and got myself some sweet utility.
Her mechanics are izi but the decision-making you need for her (especially early game) seems insane. How do you play this champ?