Katarina BS needs to end she is so strong and skill cap bs

I know that I'm not gold or plat but I can not get over that fact that out of all the champions in the assasin role kat is the most broken champs. I see not that her skills r op it is her passive it make carry even the weakest teams to the point where no one can stop and your team ends up braking down. Im mean look at this "Scoring a kill or assist will reduce the cooldown of Katarina's abilities by 15 seconds". SO when late game happen or she hits lvl 16 its gg sine nothing can stop her from kill your whole kill. Even with champions that can stop her ult she just needs to spin and hope back to her team for the clean up. I know and understand that many people will just troll and say no she is not. But for bronze teir player who cant climb because to practice in blind pick and other game types she is like a rail gun and u a target. Anther thing as far as assassin go they r meant to be squish but how is that I saw her take a jinx r to the face and with only 120 it just looked like it was a basic in terms of damage.

(Addition 2/13/15) I dont hate Kat in any way. I just think as far as assassin go she and akili r the stroungest picks next to zed and fizz. It just due their burst. From what I can tell its the fact that their damage is hybrid by that I mean ap and ad scaling on most of their skills which is hard to build against in lane. As since kat has no resource she just needs just cdr and she snowballs over u.