Syndra Ultimate!
Lets talk about 
In my opinion her ultimate is a bit too "easy".
It should reward you more the more balls you stack.
I think her ult damage should look like this:
First Ball: 50/90/140 damage + 18% AP
and then every ball deals 10 + 2% Damage EXTRA.
This way with lvl 3 ultimate if she would have 7 balls the final ball would deal 200 + 30% AP damage.
Why this change would be good? it'd mean that setup would be much more important. If you walk into a ball field you are dead, but she can't just 100 - 0 you without setting up the balls first.
it'd also be good for soloQ/ competitive balance since pro players should be better at avoiding ball fields, and thus she wouldn't be a 100% pick/ban.