Stopwatch is one of the main culprits behind League of Legends' professional matches slowing down to a crawl. Even Korean teams, once known for super aggressive early game now get frequent hour long games. Riot Meddler shared the upcoming nerf info as well as his thoughts.
Quick Gameplay Thoughts post on League of Legends NA forums by Riot Meddler left a few pleasant surprise on 14 February 2018. For starters, the single free use of Zhonya's Hourglass every champion can get through the Commencing Stopwatch rune is getting a nerf.
The rune itself will remain powerful and viable, but the time to get it ready is being shifted from six to eight minutes. This means it will not be available before champions hit level six, ergo the gank happy junglers that rely on their ult, such Nocturne, Rengar or Warwick will get one run at bottom lane before Stopwatches halt their progress.
The other issue that's actively stopping junglers from spicing things up is the abundant free vision everyone gets. Sightstone integration into the gold generating items basically slashed free ward charges' price by 800 gold, then there are Zombie Wards, Warding Trinkets, poros and then there is Tracker's Knife. A jungler item that ruins the other jungler's life.
Patch 8.4 might also get rid of the Tracker's Knife entirely , much like the Fortnite benched the SMG. Should this happen, the lack of those two free wards will mean less info on the opposing jungler's location and therefore more opportunities for kills. It will also mean less ward hopping for Lee Sin and Jax but with free wards from trinkets they will be able to overcome it. Well, Lee Sin will overcome it, Jax still needs a ward removal tool.
Meddler's thoughts from 14 February 2018 can be seen on the NA boards and right now these changes look rather satisfying. He also mentioned there will be more info on Friday, 17 February 2018, including potential nerfs to Tristana in Patch 8.5.