Where is the Balance? Specifically Fiora

Basically, I just do not see how some champs are balanced. Fiora, for example, has a dash every 6 seconds or so at max rank, which is shorter if she hits a target, giving her a lot more mobility than most other champions and her parry will block all damage and crowd control (cc) effects on her for a short time and it can return the cc back to someone. This is usually topped off with true damage from her passive which is a considerable amount when both her q and w can proc the mark and she can use her other abilities to keep herself safe. Usually these things are balanced out by some drawbacks such as poor wave clear or poor aoe damage, but a hydra gives her a comparable amount of aoe damage and wave clear. I just don't see where her drawbacks are. Darius is a very strong champ right now with solid poke, good sustain, a pull, and a slow, but he actually has a drawback. He has no escape to balance out his damage and pursuit potential. this is similar with all the juggernauts. They have overwhelming damage and they snowball incredibly well, but they lack a lot of mobility.

Anyone's thoughts on the subject would be interesting to read.