Listening to: Boob tier list:
Reading: C (fits perfectly in your hand)
Eating: B and A (they have hard nipples)
Drinking: Your size
THIS LIST IS ONLY FOR THE WII U VERSION
What makes a character viable in this game? First, waveclear: the ability to quickly clear out hordes of enemies. Damage, how hard they hit and how much their attack scale by leveling. Reach, how far its normal attacks goes, which helps tremendously when weak point smashing. Boss killing, how quickly it can diminish a giant boss' weak point. 1v1, how well it fares against other characters, such as Link. Movement speed, and dodge distance; i.e. how far you reach with a single dodge. Below is a list and explaination of the Hyrule warriors' capabilities in these regards.
Master sword Link
Volga, Rod Zelda, Naginata Impa
Sheik, Sword Ganondorf, Ruto, Midna
Ghirahim, Gate Lana, Zant, Rapier Zelda, Sword Link, Darunia, Staff Lana, Rod Link, Great fairy Link
Spinner Link, Book Lana, Fi, Cia, Medli
Baton Zelda, Giant blade Impa, Wizzro, Agitha
Those not mentioned
Explaination in alphabetic order
Agitha, bottom tier
Easily the worst character I've played. Her waveclear is terrible and her reach is abysmal. You pretty much have to stand up in their face if you want to be able to hit 'em. Her attacks are slow and you can't dodge while she's airborne during her third attack, or cancel her heavy. Which, speaking of, is not very useful. She requires a lot of practice to be used efficiently, not someone you can pick up and hope to do well. Her special doesn't reach far, either. On a minor plus side, her weak point smash attack has great reach, and can possibly hit three times if positioned well.
Cia, low tier
Awful waveclear and low damage. Can do damage with her heavy should her enemies be weak do darkness, especially 1v1. Overall, there are better characters. However, she's saved from bottom tier due to her efficiency in 1v1 with her good reach and fast weak point diminishing in her first few attacks.
Darunia, mid tier
Ok in every aspect except movement speed and dodge distance, which aren't good. Good damage and a decent special if all hits connect. Might require practice.
Fi, bottom tier
Slow movement speed and needs practice if you want to land your attacks and not slide all over the place. In truth, she's ok in her own right with a bit of practice, but she's terribly outclassed. Her waveclear is bad, regardless. Her only redeeming factor is that she'll do a bit of damage with her heavy activated against opponents weak against light.
Ganondorf (sword), high tier
Usually regarded as top tier, but I think he's not good against bosses to be ranked that high, plus that he's outclassed by Volga. That said, his special has great reach, his wave clear is absurd and he's good 1v1. However, he's slow and his reach isn't too great.
Ghirahim, mid tier
Fast attacks and good waveclear. Not a very useful heavy. Ok in all other aspects.
Impa (giant blade), bottom tier
Really bad wave clear and very slow attacks. Outperformed by almost every other character.
Impa (naginata), top tier
Not the best waveclear, but really good. High damage. Great 1v1 due to her speed. Absolutely phenomenal against giant bosses should you land you heavy (this takes practice). Really good in focus mode due to her already high damage and waveclear. Most importantly, THE MOST SATISFYING SPECIAL IN THE GAME!! Should Volga be too much for you, use this flame manipulator instead! Easily one of the best characters!
Lana (book), low tier
Apart from her movement speed, she's below average at best in all categories. Especially her waveclear and damage output.
Lana (gate), mid tier
Good movement speed and good waveclear with her dragon. Should you be lucky to get one from your heavy, the dragon becomes super fun! Unfortunately, it's luck based, which is not something you need in this game. She's ok in other aspects.
Lana (staff), mid tier
Bad waveclear but fantastic against bosses. Would have been low tier had it not been for the latter.
Link (Great fairy), mid tier
Really fun to play as! Good damage, but suuuupeeeeer slow attacks apart from her normal combo. Is saved from a spot in low tier because she becomes crazy 1v1 with her heavy activated. Should have been seperate character, though.
Link (Master sword), god tier
One letter: X. If you though Garen was spin to win, you've never played this game. Not only is Link's spin attack cancelable, it's the fastest waveclear in the game, and deletes weak points 1v1. His only possible downfall is that he's not great at boss killing and how much effort you need to get its only skill activated, which also means you can't get any other cool skills on his weapon. That's rather trivial when you're the most broken-ass character in the game.
Link (rod), mid tier
More than passable, but don't use it unless you have to. Link has better weapons. I need not give an example.
Link (spinner), low tier
Fun concept, but below average performance is just about every regard. Just use Master sword.
Link (sword), mid tier
In case the Master sword is too classy for you. Pretty much the answer to "What if you remove the spin attack, the only redeeming factor of the Master sword?".
Medli, low tier
I'm really glad she was added for free, but man, does she underperform. Her crippling weakness is her slow and ineffective waveclear. However, I'm glad they kept her classic wing flapping sounds and her moveset is about what I expected.
Midna, high tier
Would have been mid had it not been for her waveclear. Good damage and a very satisfying weak point smash. Good movement speed. Ok in other regards. Hands down the most satisfying weak point smash in the game.
Ruto, high tier
Her reach is bad, but she's absurdly good against giant bosses. Her waveclear is really good (as it's literally a wave), though her special doesn't have the best reach. Good movement speed. Not the best in focus mode since her strong attacks are somewhat slow. Solid pick overall, but might require practice.
Sheik, high tier
Definitely needs practice as her strength lies in using her songs, especially the water and light ones. Surprisingly good waveclear, decent damage, and can spam specials if used efficiently. Keep in mind that her songs are slow and are lost should you dodge cancel them too early. Might not seem impressive at first, but is probably the best lightning character in the game.
Volga, top tier
INSANE waveclear and really fast attacks. Can dish out a lot of damage even at low levels. Hands down one of the best characters in the game. The only bad thing I can think of is his movement speed and that he's not the best at boss killing. His dodge doesn't reach far, but you don't need to avoid anything when you're this strong. Did I mention he's invulnerable during his dragon nuke?
Wizzro, bottom tier
This guy sucks. You really need to level him up due to low damage and scaling. Only then is his waveclear ok. He's good 1v1, but there are WAY better characters out there. Don't use him.
Zant, mid tier
Borderline high tier. Great waveclear. Held back by the fact that he needs to spend his meter in order not to not fumble. Not the best 1v1 due to his reach and short dodge distance. Ok against giant bosses.
Zelda (baton), bottom tier
Ok 1v1, but she's slow, has awful reach and bad waveclear. Her special is ok. Bad dodge distance. Not exactly a good pick, only use her if you have to.
Zelda (rapier), mid tier
Borderline low tier. Her waveclear is bad, but she's good 1v1. Unremarkable is the best word. Except for her special.
Zelda (rod), top tier
Bad dodge distance, and she's only effective with her first statue turned on (which you must manually refresh). However, with practice, she's one of the best in the game. Absurd waveclear (if a bit slow), spectacular 1v1 and boss killer, and has a really satisfying special. It's worth getting a Zelda amiibo just for this op weapon. Struggles in focus mode since you must refresh your statues and her attack speed is slow.