Someone else recently shared this because they were confused by this, and I'll admit it is kind of confusing in the way that it is worded on [Surrenderat20](https://www.surrenderat20.net/2018/10/1015-pbe-update-tentative-balance.html)
I think I explained it in a way that made sense to them so they decided to delete their post, which is unfortunate because it would have been good for others to see if they were also confused.
Basically, her passive is no longer an execute in the sense that the total damage dealt is no longer equal to a percentage target's missing health. Instead, detonating 4 stacks of plasma now deals a flat amount of damage, regardless of the enemy's total health, that increases significantly based on the percentage of the target's missing health.
So it is weaker against tanks.
I think this is a good nerf.