Here's the team I think we'll see once Kai Sa gets introduced.
Your Thoughts
(2) - (4) Knight (with one Knight's Vow)
(3) Noble
(4) Ranger
(2) Phantom
(3) Assassin
(2 Invulns)
7 Comments
Void is getting nerfed, no need for Kassadin if you can’t fit a 4th (Cho’Gath/Rek’Sai)
Phantom is too RNG to be reliable and only really synergizes with Karthus over Morde (still not worth running).
Better off scrapping Knight & Phantom buff and run 4 Void, 3 Assassin, and either Glacial 2 or Demon 2 (with Varus over Vayne and Evelynn over Garen) to make use of the hits on Ashe or Varus for unit control. Much better offense with modest CC rather than relying on RNG to Kayle ult the right units and Phantom to target something useful.
+ 
i think if you replace kassa with cho, it's getting somewhere, also drop the kayle or garen for an reksai cause you need 4 void for the buff next patch, and you'd need more assasins unless you find a ghostblade....
However, i don't think many setups will be built fully around her, cause as a tier 5 she'll be to unreliable to get.
I think it's more likely to see her appear in normal assasin/voidsassin+brawler or ranger comps replaceing some low tier pice once you find her.
Else, i think the most likely would be 
(4)void
(3)assasin
(4)wild
(2)brawler
Lots of CC
one free spot for either:
(3)shapeshift
(4)brawler
(2)ranger
And those boosts snyergies well, makeing kasia and kah crit for truedamage with increased AS while they can't miss, so there is no defensive option against it at all. either you kill them first, cc lock or die.