Mage Item Suggestion (might be op)

I am no expert on game balancing, and to be honest I was bored and was looking to make a post about balance. I was looking at the items and found Wooglet's. This item isn't available for SR. It is a strong item, but for a reason. Mages on TTL aren't as viable as SR. So giving them an item like this is necessary. But I honestly think that adding this to SR would be a healthy change.

Wooglet's Witchcap 100 AP 45 Armor U.P Increase AP by 25% U.A becomes invulnerable for 2.5 seconds. (Zhonyas active) Cost:3500g

This is really good compared to both Zhonya's and Deathcap. I think that possibly removing Zhonya's and Deathcap and replacing it with this would allow Riot to add more diversity to mage builds. Also I know you guys at Riot said you were more focused on reworking items than making, but if you made this available for SR I think you guys would have some room to start pumping out diverse items.