Yasuo E is point-click ability affecting single target. You click on target, you dash through that target.
Fizz Q is point-click projectile AoE. Yes, it's ridiculous since the only thing AoE about it is W's Passive application and even then that's recent, however it is target-dependent AoE. Just like Lucian's Q, it requires target and it is set based on the target, but affects the area. In Fizz case it affects the area in one way and additionally deals damage to the primary target If they stay in the affected area.
I'd say with Panth it's him being outdated and having outdated point-click behaviour. Some time ago, If you flashed out of Annie W or Cho W while they are in cast animation, it would still affect you. It was outdated behaviour as the cast-time was intended to be "what stops you" not "delay counterplay". The philosophy has changed and the cast-times of such abilities became both "what stops you" and a delay that can be used for counterplay. Thus, several months ago it got fixed.
In the same way, once Riot settles on their philosophy about these things, he'll get updated appropriately.