Ok here's the thing about blade waltz, ESPECIALLY in a Team fight. Firstly it's not as Broken as Warwicks ulti because warwick does an INSANE amount of single target damage. You're literately able to take a 2k hp squishy end game and kill them with Warwick ult. Hell you can do this at level 6 as Warwick. As Fiora using the ulti on a single target the ulti NEVER 100-0 the target. each strike does less damage to begin with and despite having near 200 attack (f you build right early on) you still wont 100-0 a target with blade waltz. Even worse in a Team fight where your ulti kinda only hits the target you selected a few times rather than every hit of the ulti, so it kinda does less damage in team fights since the hits are being split up. Fioras are so dominant because of their dueling ability and the versatility to extend that dueling into a team fight.
I can get into the back line with my ulti and pick off low hp targets with Q's, E, auto's and any active items I have (Hydra, youmous, etc). Warwick can delete a single target and sustain all day in the team fight, but he does it by locking them down while everyone watches. So it's frustrating because the only counter play is an item which not everyone is going to build. If a fiora get's in your back line you can counter play her because shes squishy and using autos. With enough CC (really only one good targeted one well placed) shes sorta dead. Warwick will sustain and probably be tanky, so even if he is cc'ed it's not like your deleting him unless you have a really fed team. Not to mention is ulti has a lower CD.
