According to a tweet from Yusui, Piglet's been benched for his toxicity, not his performance (which backs up Xpecial's vlog from last week where he more or less said the team environment was awful). I assume he was better behaved back in his SKT T1 K glory days.
C9T, and all their starting players, have been banned from the Spring Challenger Series for fielding a ringer (their analyst played a qualifier game on their support's account since he'd failed to update his client). Teams still not making sure their tournament clients are ready well in advance after all the incidents (most famously NiP Zorozero) is kind of hard to believe with all the effort that goes in to an LCS challenge.