The stats are up on Runeterra.Ar, and I have some personal experience with it as well. The site's data shows about 8.5k games played, making it a whopping 17% playrate over the past two days, which is pretty insane. About double the playrate of anything in the past few months. But its winrate is only about 53%.
Yes, it can highroll pretty hard. Yes, it's actually a good deck now. No, it's not as OP as people think it is.
Examples of decks that beat it:
- Elise Spiders - mono-shurima is actually listed on Runeterra.Ar as the best matchup currently for spiders. Spiders deck has a 1.5% playrate and a 55% winrate overall - no doubt thanks to the easy wins from all the mono-shurima players
- Azir/Irelia - mono-shurima is also listed as the best matchup for this deck as well - this deck that got nerfed hard in the past and fell off the scene for a long time. Well, it's back, and it's eating mono-shurima for breakfast. Azirelia's playrate is at 2% and winrate is at 57%.
So, yeah, guys. Don't fall into the trap of the alarmist hype that mono-Shurima is completely broken and OP. It just isn't.
Side note - I played 5 games with the deck in Plat 2 and lost literally all 5 games. Never touching it again. Time to play decks that beat up on it, so I can get back my lost LP. Also, just for fun in normals, I played an old poro deck with Fabled Poro and such, focused on building a buffed board of all types of poros, and I queued into mono-Shurima all three games so far, and I completely wrecked my opponent in all of those games - with poros. Seriously, the deck can't be that good if it folds to poros. (Edit - though, to be fair, I did include two copies of Aftershock in there, and those did have an impact on two of my wins. In one of the wins, the opponent put their Xerath into a landmark, preparing to level him when he popped out the next turn. Aftershock ended that dream, and the game. In the other game, the opponent didn't bother to spellshield the Sundisc, so I killed it. Third game, I just beat him the normal way.)