For those of you who havn't read the patch notes, her passive Fleet of Foot MS increase now also procs off Ricochette (including bounces) hits and boomerang blade hits on champion.
It did increase her kiting and escaping slightly as when she is running, she can hurl a boomerang against chasers to up MS for better running away. In the similar fashion it ups MS too. Procs off rico help in chasing and escaping too. You can aim a minion with rico for it to bounce to enemy champ and get MS advantage over them in times of chases and escapes.
So you think this will increase her above some other carry or is she still pretty much low tier and counter only to blitz lanes?
The lack of CC on Siv makes her overall play slightly dubious and very poke-centric. That is "ok" for an ADC, but you need the team to compensate for it.
I think she would do great in a poke / kite team, e.g. a trundle jungle and/or Jayce mid/top, with CC support.
Probably a Sona to counter hard engages or Thresh to initiate. Or, probably Lulu for a 2v1 swap with bonus CC/hp on your hard engage. Throw in some composition of Rumble/Kennen/J4/Anivia.
Basically Sivir becomes an over-time MF instead of a one-shot one-burst MF, with bonus epic waveclear and split pushing / team steroid power.
That would actually be pretty interesting: Jayce - J4 - Anivia - Sivir - Lulu. You could siege with poke basically forever, and have pretty ridiculous disengage.
The Sivir passive tweak ... shrug. Will help her laning phase a little for sure.
I think her biggest issue is the sluggish AA animation and projectile speed. it's hard to attack walk with her, especially when you're trying to use her AA reset in tandem. Most other ADCs can fire off an attack without blinking. In addition, this delays her passive proc. Overall tedious.