Simple Solution to Rift Herald Problem
Make it so the eye only shows if 2+ champion are within 750 units of it.
No more people soloing it
Make it so the eye only shows if 2+ champion are within 750 units of it.
No more people soloing it
Why is people soloing herald a problem? Is it much different than soloing baron? I'd imagine most champions take damage off of it and if a team is completely ignoring vision control of that area it's their issue. How does this differ from someone soloing dragon?
Also, as for your solution, a jungler or even top/mid could solo it and call for the top/mid laner (or jungler) to come when it's almost done just to pick up the eye...