We need to talk about mobility and their trade-offs
WARNING: This is a QQ post about 
.
When you give an ADC champion high sustain damage, high mobility, and utility/cc, I don't think you get to say that their trade off should be a lack of burst damage. Isn't that how ADCs are defined? When you decide to give someone burst, such as 
, you take something away; such as his sustain, range, and giving him a mana-hungry E until you max it. Riot was doing a good job in curbing mobile ADCs. 
has a more expensive W, and 
has a long cooldown on her W.
Looking at 
, she's labeled as a pure fighter. She has high sustained, decent mobility and knock-up, should her only weakness be that she can't burst? Isn't that what fighters are supposed to lack? To be fair, she's also very vulnerable, even when building tank, so I suppose she's in a better spot.
Then we get to mobile mages. You have 
, the mage/assassin who trades mage burst and safety for mobility and an assassin-like playstyle. 
on the other hand, trades mage burst for sustained and mobility.
These playstyles break the mold for their roles, without "entirely" ruining things for others. I'm not entirely saying Kalista ruins ADC viability, but Riot needs to think more carefully the next time they make a mobile champion. Even when you tack on a weakness, there is such a thing as too much strength.
, however, can go entire fights without using Safeguard's dash (he can even cancel the dash to just use the shield), and has no real deficiency in his kit that forces him to use his gapclosers, which is why his mobility often feels irritating to deal with. If he had a serious, exploitable weakness that required him to use both his Q and W dashes, then he'd be fine.
, 
and even 
can handle her (plus really recent champions like Rek'Sai and Mega 
), because their kit still allows them to do useful stuff even when they get kited super-hard, with or without mobility. On the other hand, champions like 
or 
get hard-countered because they're built in such a way that they're either too good if they can reach their target, or literally useless if they get kited (pre-rework Sion would also suffer from the same problem if he were still around). Ranged champions can already deal with kiting thanks to their range and overall reach, but a lot of melee champions just don't have the proper tools to deal with kite champions at all, which is why a lot of them do really poorly against the absolute best kiter in the game.
say what?), but it also means they tend to shred anything in their range. Darius is a PERFECT example of this. If you can kite him, you're solid. If you're caught, you're probably screwed.