Mobile AD casters aren't fun
OK yes, this i lost and i'm frustrated so this post is being made, keep that in mind, but don't write it off as a rage post.
http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1759471131/32122784?tab=overview
this is the kind of game which always turns me off from playing league of legends, because frankly it feels like the direction the game goes is completely out of your control, there is literally never a point in the game which we were ahead, the enemy had such naturally strong champions, and even despite being completely AD, couldn't have their damage nullified or realistically mitigated.
They effectively start out ahead, but let's say you rush armor, it's far to easy for them to just rush
/
at which point you're wasting gold to build armor, they will still kill you with the burst from their abilities. If you instead build health, they might not have enough damage on their abilities to kill you, but because they are all AD, they can fall back on their auto attacks as a source of consistent damage, which you also have no answer for.
Though how about we be optimistic and say that it's an even fight at some point, the vast majority of the time, your get forced into a situation where either you lack the damage to out duel the enemy, or despite being able to out duel them, they have so much more mobility than you that they can escape at any point when they start to lose the fight. You don't have a source of consistent damage like they do, so you have no option to not use your CC to secure the kill when it's the only way for you to out duel them, but they do have that option.
I've never been a fan of AD casters being added to the game, an ability here or there was always fine, but champions who have a kit built completely around scaling with the stat, just turn me off and make me question how balanced the game would actually be, if people would just stop playing the meta and play the most powerful champions. Sure there are some AP champions who are very powerful, but it tends to be a result of kit utility, not simply the virtue of having all AP skills.

can get into someone's face,
are given crazy mobility instead of powerful initiates. In light of that they are given freedom of movement, they don't have to commit to an attack. If a make a decision they can escape if they fight doesn't go in their favor.