This game, has a major problem

I am sorry, and I am expecting a lot of "qq" and "cry more" or "git gud" reponses, but this game has a serious balancing and gameplay problems. Skillshots with hitboxes bigger than the actual particle effects, skills not completing even though they were fired pre-flash, but then a flash occurs and suddenly your skill disappears into thin air dealing no damage, but the worst of all happened today. I was playing Vi jungle, and I realized something, Attack Damage Fizz, is better than Vi in the jungle, and does as much damage as Ability Power Fizz, for literally no reason. He built a Trinity Force, Blade of the Ruined King, Attack Damage jungle item, Warmog's Armor, Frozen Heart, and boots. He had almost 300 attack damage, over 3000 health, and almost 250 armor, and a base 100 magic resist. How does this make any sense with the kit that he is given? He was able to use his Q on my teams zed, and granted zed was underfed, he took out over 3/4 of his HP with just that one Q, and it made no sense. The part that probably frustrated me the most, was the fact that flash apparently now nullifies abilities, I went to gank a katarina, and began charging up my Q as Vi, and suddenly she flashed towards me, not through me, and not through my skill, she flashed before I even let the skill go, landed a few minion lengths infront of me, but my dash went straight through her, and she used shunpo to get to the safety of her tower. The laner on my team who was against katarina saw the exact same thing I did and was equally confused. I do not understand why this game has such massive gameplay flaws and balancing issues compared to other games I have played.