This is the champions in a nutshell imo
Orianna -> good ult + dissonance = ace
late game powerhouse, just do a farmfest early game
insane utility
good waveclear
cons - not THAT mobile
- weak early but she can farm safely so that's not a big problem
- difficult in terms of mechanics
Lissandra -> incredible CC
strong throughout the game
has free zhonyas (good against assassins and towerdives)
superb teamfight, ult does AoE dmg wtf
mobile
cons - "short" range for mid lane
???
I don't even know, her kit so much to offer
Ahri -> mobile
true damage
DFG -> R W ignite Q R RR R R RR R R RR -> ???? -> profit (DFG = powerspike)
cons - skillshot
charm-dependent for assassination
Shorter version
Ori - want to delete their whole team late game? want to provide utility for your teammates?
Liss - want to delete their ADC? want free zhonyas? want to see the enemy zed cry? want to CC chain your enemies?
Ahri - are you good at skillshots?