If I were building Shyv I think I would definitely want Randuins, and either BoRK or Hydra, probably BoRK though because she has no real CC of her own though and the attack speed has too much synergy with her kit. Ulting at their carry with Randuins and BoRK would be hella scary though and I don't think you're getting away outside of blinking over a wall, but that takes away a lot of the threat of AD's not named Ezreal for a couple seconds while they get back into the fight; I would consider that a job well done on your part.
If you are snowballing then sure, go Hydra after that, but I think BoRK is probably the only damage item she needs to get the job done. As long as you can stick on somebody, which Randuins and BoRK will let you do very well, your sustained damage should put in hella work.
That said... she still has no ganks... So her biggest problem still exists, and it's not like they are going to be changing that any time soon. Or ever... Because it's just part of her character now.