Alternative Vision Option With Removal of Tracker's Knife

How would people feel with adding stealth ward back, but make it an Invisible Ward? The ward cost could start at 100 gold, and could scale with the duration of the game to be more costly . It would last the same duration as a Warding Totem ward, but could only be revealed by Sweeping Lens or Oracle Alteration (Control Wards would not reveal it). Limit it to only have one of these wards in your inventory. Below will be an explanation of my thoughts on this.

This would give everyone the option to purchase extra wards to place. Scaling cost would limit the amount of wards that would be purchased at any point in the game (especially late game if you made it a 500 gold cost). It would take up an inventory slot which would also limit the amount of wards in the late game. Only having the option for one in your inventory, and the shorter duration would limit the amount of wards early game. It would add some strategies to play around Control Wards especially with the new scaling of secondary Elder Dragon and Baron buffs, but would still be vulnerable to being cleared with Trinkets.

This, I believe, is a decent alternative to Tracker's Knife. I want to know what others think.