Thresh
One of the best champions in the history of competitive League of Legends, Thresh has remained in top form throughout the season. Riot has tried to apply the odd nerf to open up the options available in the botlane, but to no avail -- Thresh shines no matter what.
His presence has remained constant throughout all versions of the summer split and everything seems to indicate that nothing will change too much as we head into Worlds.
Few alternatives mean the champion who registered a 72.9% presence throughout the summer and was one of the most prominent characters at MSI will likely continue to be so at Riot's showpiece.
Other candidates
Although there aren't any real alternative to fulfil the same role Thresh inhabits, there are a few supports who point towards improvement by the end of the season.