TenZ has only ever played good against MDL teams. Cloud9 was his chance to play tier 1 teams and instead of committing to the project he disobeys his IGL on server and then complains in his stream how he doesn't get everything he wants. And he still played like shit the whole 3 months.
TenZ might one day become a good player, but it's obvious that he isn't yet ready to play in a team that wants to challenge for trophies. To have a future in a tier 1 team you need to be able to do as you're told by the team captain and not completely shit the bed with your performance. TenZ failed both of those things.