Please don't leave Skarner's spires as they are now
First off, I appreciate and like the fact that Riot is willing to try some very new and creative ideas on champs. That being said, this new Skarner passive is too "feast or famine", which was what the first rework was trying to get away from. If you're ahead, you will have vision of the enemies jungle without needing wards and places that are similar to trundle W's. If you're behind, you give the enemy free gold and more vision over your own jungle, thus putting you even further behind. Furthermore, they make invading for both teams nigh impossible with the extra vision they provide.
I can't really say what to change the passive to, but just don't leave it like it is now.