OK, while Worlds 2019 has certainly been one of the best from a meta perspective, with a very wide variety of champions seeing play (99 out of 145 champions have been picked or banned) and nothing notably horrible like the infamous Juggernaut patch of 2015, there has been ONE big standout problem, like a zit on a supermodel's face, and that is (obviously) **Pantheon.**
According to lol.gamepedia, Pantheon has a _100%_ pick/ban rate across all 117 games of Worlds so far- banned 116 times, picked once (he won, although the K/D/A wasn't that amazing). Such a universal ban rate pretty much telegraphs that Pantheon is _so_ utterly broken on the Worlds patch that the teams know that, if left unbanned, he WILL 100% be picked, and there are either no counters for him, or so few counters that if they let the opponents choose him they'll simply ban the counters to make him unstoppable (otherwise at least ONE team would have left him open to counterpick him).
This means that Pantheon has arguably been one of the most game-warping champions in pro-LoL history _without even having been played._ Why? Simple: _every single team_ who gets red side only gets 2 bans in the first ban phase, because EVERY one of them MUST first ban Pantheon. And every single one of them HAS. It's been automatic- blue side bans, then basically gets to ban again because red automatically bans Pantheon without even thinking about it. Bans are valuable, so it can't just be a case of teams being too lazy to work out how to deal with him- these are the top players in the world, and if not _one_ of them has worked out a proper counter to Pantheon, instead just choosing to forfeit 1/5 of their bans in half of their games, there _is_ no counter to Pantheon.
In all honesty, once it became blatantly apparent that Pantheon would never again be allowed to be picked in this Worlds (by the end of Group Stage at least), Riot should have just disabled him to remove the handicap from red side teams. Clearly he's so utterly broken that he shouldn't have been allowed to be played at Worlds, because every pro team has reached a consensus that he _won't_ be played at Worlds. So soon after his relaunch, its baffling that Riot allowed him to be played on the most important competitive patch of the year. Again, this has been a pretty damn good Worlds patch, which just makes the Pantheon blunder stand out all the more.