Any champion that can ignore/block towers better have some huge drawbacks, That's 99% of the reason Akali was nerfed. Her W had 0 draw backs. Diving was easy, so all she had to do was get ahead and nonstop dive you. Fiora Blocking it would have similar repercussions. I dived you and now 1 shot is left nope I just block it now.
Pantheon and Bard can do it as well, but it has drawbacks. Bard: You can just get yourself ulted too and the effect is negligible.
Pantheon you can AA before the shot. Fiora having an on demand block and Akali having an "I'm untouchable button." Are too strong. Granted Fioras W wouldn't be as broken as Akalis, but that's not the point.