Can you 100-0? Do you have 30+ dashes? Do you ignore tank stats? Can you use duskblade well? Can you abuse stormrazor?
If any of these answers are yes, you work
How to tell if the champion won’t work.
Do you do sustained damage? Are you a true tank? Are you immobile? Do you lose to assassins? Are you currently not in riots approved flavor or the month?
If yes, you are worthless.
DuskDaUmbreon4 votesTop 20 champions:
Of these, Ashe, MF, Cass, Nami, Zilean, Ziggs, Kog'maw, Anivia, Heimer, Malzahar, Karthus, Brand, Sona, and Zyra have no dashes (technically Ziggs does but it's not really significant enough to bother with). That's 14/20, from spot number 1 to spot number 20. The top 3 have no dashes.
Of those 14, Ashe, Cass, Nami, Zilean, Kog'maw, Malzahar, Karthus, Sona, and Zyra all lack lethal burst damage with their standard build (so ignoring full AP Zilean, Zyra, and Sona). Of those not mentioned: Kled also lacks lethal burst damage.
Of those 9 who we have not eliminated, none have true damage, and only two of them have resistance shredding (Karthus and Kog'maw). Only Kog'maw of that list has %hp damage.
Of those 7 who do not shred/ignore tank stats, none can use Stormrazor or Duskblade. Only Wukong, Shaco, and Miss Fortune, out of the top 20 champions, can use either of them.
Comparing our final list to the criteria that says a champion cannot be useful:
-enhanced autos being core to her damage output, is one of the squishiest champions in the game, isn't truly immobile due to her E giving her a lot of speed in late-game, but lacks any kind of dashes, and does absolutely terribly against assassins or assassin-like champions, yet she's still number 2 in overall winrate.Hmm. I think your list may be slightly wrong.
The thigh guy1 votesTop 20 champions:
- Zyra
- Sona
- Brand
- Ahri
- Karthus
- Jax
- Malzahar
- Shaco
- Kassadin
- Heimerdinger
- Anivia
- Kled
- Kog'maw
- Ziggs
- Zilean
- Nami
- Cassiopea
- Miss Fortune
- Wukong
- Ashe
Of these, Ashe, MF, Cass, Nami, Zilean, Ziggs, Kog'maw, Anivia, Heimer, Malzahar, Karthus, Brand, Sona, and Zyra have no dashes (technically Ziggs does but it's not really significant enough to bother with). That's 14/20, from spot number 1 to spot number 20. The top 3 have no dashes.
Of those 14, Ashe, Cass, Nami, Zilean, Kog'maw, Malzahar, Karthus, Sona, and Zyra all lack lethal burst damage with their standard build (so ignoring full AP Zilean, Zyra, and Sona). Of those not mentioned: Kled also lacks lethal burst damage.
Of those 9 who we have not eliminated, none have true damage, and only two of them have resistance shredding (Karthus and Kog'maw). Only Kog'maw of that list has %hp damage.
Of those 7 who do not shred/ignore tank stats, none can use Stormrazor or Duskblade. Only Wukong, Shaco, and Miss Fortune, out of the top 20 champions, can use either of them.
Comparing our final list to the criteria that says a champion cannot be useful:
- Zyra - Does sustained damage via her plants, is not a tank, is immobile, and does fairly neutrally versus assassins, yet is still the number one champion in League by winrate
- Sona - Lacks true sustained damage, although she gets close with
- Malzahar - Does sustained damage with W, E, and R, is not a tank, is completely immobile (lacking even a speedup from runes), yet still does well against assassins due to his R.
- Zilean - Does not do sustained damage (merely lacks lethal burst damage), is not a tank, isn't immobile (although he lacks a dash) due to his E, and does well against assassins due to R.
- Nami - Does some sustained damage through E (W?), is not a tank, is low-mobility (although has a few small speedups), and does rather neutral versus assassins (it being mostly a test of skill between the two).
- Cassiopea - Sustained damage via E, not a tank, no mobility, and I honestly don't remember how she does versus assassins.
- Ashe - Sustained damage with almost all of her kit, not a tank, no innate mobility at all (and is in the lowest tier of base MS, although she can get MS from runes and items), and is terrible against assassins.
Hmm. I think your list may be slightly wrong.
Zyra. Made to 100-0 Sona. Builds Lichbane. Tries to 100-0 Brand. 100-0 Ahri. 100-0 Karthus. Just abusing adc being shit.
That’s the top 5. They all do the same fucking thing. Try and instant kill someone with little to no counterplay. So they all fall into category 1.
Jamaree3 votesThen you look 
and 
As they have high win rates and ignore the top metric of your post and fit into the bottom one, but ok.
Moody P1 votesheimer bursts and karthus will kill you in 3-5 Qs, doubt that's what he's gunning for
Jamaree1 votesI mean what apc doesn’t have burst, they all burst, the only one that doesn’t burst is Cass and even her win rate is higher then Zed’s
TheSingularity1 votesWhile karth melts people. Heim can certainly 100-0
Ult E+W+turret lasers decimates just about anyone
The thigh guy1 votesThen you look
As they have high win rates and ignore the top metric of your post and fit into the bottom one, but ok.
Um? Donger instant kills with his missles sooooooo he fits into 100-0.
Karthus is just abusing the fact that adc is a shit role.
Dorans Pants2 voteswhen you are forced to play blind pick and the only champs you see are:
cancer as far as the eye can see