Lingering Vision

I'm curious about your impression on the potential strength that would come from something like lingering vision.

In case the term is not clear, this would essentially be a mechanic that would prolong the duration vision will persist after a player has left the general area or some vision granting item or ability has been removed, timed out, destroyed, ... ect.

Depending on the strength, I wonder if it would be possible for implementation in different forms ranging from a singular champion passive to an item passive that could be available for anyone.

In the form of a champion passive it could have a differing level of strength from only granting a lingering vision for vision gained by that champion alone, or they could offer lingering vision for every allied champion.

The application of this as an item passive would of course make the most sense being applied for vision granted by the champion with the item.

The amount of time vision lingers is of course a very important factor for balance as well, and I would imagine that Riot would ultimately need to decide what would be balanced, but I'm curious what, if any version of this even sounds reasonable.

Simply to start this off, I would like to consider this being a passive granted to Ruby Sightstone. Currently, the only reason to take Ruby Sightstone over Eye of the Equinox is because it is cheaper and/or because you would rather have one of the non-vision granting support items.

This is just one example of how I could see something like this being added.

Please give me some of your thoughts and ideas.