Why was Twitch buffed?

Correct me if I'm wrong, but wasn't Twitch on a winning LCS team not so long ago? I thought we're supposed to nerf champions after they do well in LCS, but it seems the opposite happened here. Maybe Twitch isn't FOTM like other champs, and maybe he's having having a hard time in the so called "tank meta" (which doesn't exist at all), but Twitch is far from a weak champion. This buff was not needed at all. SSW clearly demonstrated what a strong pick he is, so instead of buffing a champ who is already strong, why not buff champs who actually NEED buffs, so we see more diversity at LCS this year?