Sivir
What to Keep:
She is a good beginner's ADC in order to get used to the role due to her abilities being straightforward. While I would not want to change any of the functions of her abilities; I do feel some changes would be good. Still, keep her Q-Boomerang Blade and E-Spell Shield.
What to Change:
P-Fleet of Foot: keeping her movement when she hits an enemy; I would add another Passive as this one alone feels on the low power side. Calling it
"Syn-Energizing"; it would make it so Energized attacks deal extra damage to Champions. but their effects are lower. Fleet of Foot would be also consider be buffed from Energized effects. While lowering her utility, it would buff her synergy with items that also use Energized and also giving her more guaranteed damage.
W-Ricochet: while the active of his ability is great, I do not like how the AS buff is tied to her Ultimate and not this ability. I would move the Ultimate passive as her W passive and scale it so is balanced.
R-On the Hunt: passive being moved to her W; I new passive would come in as the following: while On the Hint is active or while the duration of a Energized attack; this unit is able to walk through units. This would bring a new dynamic to Sivir as to whenever she has Ultimate or when prepping an Energized auto, she is really able to go on the Hunt.