Could someone explain why the following champions became relevant/viable in pro play, mainly:
Trundle Yasuo Obviously they work, but why? Trundle doesn’t bring that much to the team play table without a way to get into the fight, and yasuo is abusable at certain stages
Trundle: Good early game to jng squimishies, ability to make a tank vulnerable later, pilar in pro play> pilar in soloQ, and most important: (soft) counter to Olaf, who is really strong in pro play, Trundle has been played a lot more since Olaf started to be meta, not a coincidence.
Yasuo: Splitpush and 1vs1 potential but only Caps shined as Yasuo imo and they still lost the game, I'm not a Yasuo fan.
Yasuo is a rare sight that gets picked for picks in the early-mid thx to his followup on knockups and the sidelane preassure in a 1-3-1 he can create, mostly as counterpick to other splitpushers like ryze that would dominate most others in a sidelane but get beaten by yasuo.
Trundel offers alot for his team, to a point where he even was common as support at times. His Pilar is one of the most potent controll tools in the game, it has a huge range and is instant and has a mini knockup, so you can intertupt any channles reliably from high distance and easly put any low mobilltiy champ in a bad spot without really commiting himself. He can do the zoneing of a tank without ever getting close just with his Pillar... Then there is his Ult that turns any tank into a squishy and ensures you're team wins front-back teamfights while also becomming very tanky himself in the process without needing much gold for it. Paired with his pilar, that makes him supreme at countering engages: The enemy tank engage, you place the pillar between him and his team to prevent followup while useing you ult on him so you're team can easily focus him down. On top of that, he's one of the best early duelists so in the early jungle, he can invande and fend off invades ratehr easily and also clear pretty well, while in a sololane he will win most splitpushes, especially vs tanks.
They picking fucking trundle like for years -_- Every fucking season there is 
And for some reason he gets no attention from RIOT. AT ALL.
In pro play it's all about closing the game ASAP. These two champs bring that kind of fast stopping power to the match and team fights.
As previously stated in some of the comments, Yasuo is a powerhouse from early to mid game (when he gets 100% crit from 
, the +50% crit damage doesn't matter too much)
When combined with Trundle, who can displace using his pillar, can enable Yasuo to ulti and take out a target. Aside from the synergy between the two. Trundle I would say is another mid game powerhouse for the sheer fact he steals stats via his ultimate. Basically, the enemy tank buys Trundle his stats ultimately letting trundle build just a little bit more damage to supply for his team. It's been seen a lot with 
on Trundle. He just doesn't die with those.
Trundle is countered harder by Tabi and Bramble than any champion not named Aatrox. He's fine in SoloQ. He's picked to make a tank a lot weaker in teamfights, and tanks are popular atm.
