When things like Trundle and Nocturne are sitting around waiting to have their kits modernized so that people can play them again.
Garen didnt need modernizing, his kit functions at all elos, he has a 53% winrate at plat, so wtf are you doing partially reworking him?
Redirect your effort at doing something like....
Pillar of Frost: First cast- Trundle places a Pillar of Frost that slows nearby enemies.
Second cast: requires Trundle to be in melee range of his Pillar- Trundle smashes his Pillar of Frost, dealing damage and slowing enemies in a cone shaped skill shot.
Map goes dark.(same as now)
Nocturne becomes the epicenter to a smoke cloud for 8 seconds(Think Graves smoke grenade, except mobile).
Nocturne point and clicks a target(same as now).
enemies within the smoke cloud can see and hit Nocturne.
Enemies outside of the smoke cloud cannot see or target Nocturne, but can hit him with skillshots.
Enemies within the smokecloud are blinded to the outside.
Enemies outside of the smoke cloud are blinded to the inside.
There you go, wow so hard.