I am not familiar with Illaoi, but I can say that what you have in your tier is true in the case of Yi, Jax and Darius. I am not sure about Fiora though... She is not an easy champion to play with, although I would say that she is an interesting champion... <3
anyways, this was posted 3 years ago so maybe you have changed your mind or added few more champions... So, who knows xD
I have to say that i agree 100%. Darius is someone i have never practiced with at all, but if i select him i can constantly do well. Master yi is also another champion that i never play myself because he is not that interesting to me, but when i meet him, i have a really unfun late game.
anyways, this was posted 3 years ago so maybe you have changed your mind or added few more champions... So, who knows xD