Zz'rot scales with health OR mana
I've been wondering about a small change to Zz'rot that would make it a good pick for the squishy supports. I play lots of support and love picking up items that really feel like they have an impact outside of fighting. Zz'rot is a great support item, but because of the way the empowered voidspawn scale, it doesn't have quite the same impact for the squishy supports. True, the resistances and movement speed are still of benefit, but the lane pushing power isn't as strong.
In the interest of increasing the pick diversity for this item, my suggestion is to change the item so it scales with a percentage of health or mana, whichever is higher. This percentage doesn't need to be same amount, but the system calculates and gives the voidspawn the better value.
You could argue that this is the point of Banner of Command, but I think Banner is a little different. An advantage of Zz'rot is that it forces the enemy to deal with this new objective (destroy the gate) or else lose a turret. While one enemy is off doing this, the team that placed the portal has a good opportunity to pick a fight in their advantage. Banner doesn't really have this presence as you don't really know there is an empowered minion coming down the lane and once it's dead, you are fine.
In short, Zz'rot is a great support item, that could be utilised by a greater number of supports.