Lissandra's new passive vs. Kog and Sion
As it is, as far as I know, Lissandra's new passive doesn't apply to Kog'maw or Sion until after they've lost control after death. Which is just plain ridiculous. Many times at that point the enemies would be going the opposite direction from where the Sion or Kog traveled with their passive, rendering Lissandra's ability completely useless thanks to its limited range.
And that makes no sense in the first place. It should activate on the actual death, regardless. It's not like the death timer or similarly coded revival effects happen after their passives are done, so this should be no different.