Yeah, this works, but it doesn't solve the problem that Pinks pose for stealth champions, nor does it actually address the underlying issues of stealth!
Having the ability to drop an instant speed (no cast time, no delay on activation) AoE of True Sight on a stealthed champion is BS. It's unfair to the stealth champ, and it's not really a test of skill on your part.
There is so much Riot could do to make vision in the game fun and exciting. Your proposal is part of the problem, in that it keeps perpetuating the idea that access to more Pinks is what we need. It's not. We need more variety in the way vision, sight, stealth, detection, and vision denial are expressed.
Riot, please.