He's bot a bad actor. But his acting here was too over-the-top and the director made a poor choice to not rein him in. As a characte4, Thanos could have been more, but this acting choice made him more comical than needed.

Do people even how the first season of Heroes ended? It was a lackluster end to the build up of all season. Really, the show only had a few great moments (not episodes but moments) through its whole first season and it's dive into contrived mediocrity was completely expected in the following seasons.