I think comparing it to Death Note doesn't make much sense because the two shows have completely different genres, setting, plot, etc. There are some similarities but they're mostly superficial.

Death Note focuses almost entirely on a battle of wits between two geniuses, while Code Geass focuses a lot more on the themes than just Lelouch outsmarting everyone.

Sometimes people get disappointed because the show isn't what they expected. Although Lelouch is very smart and proves it often, the show focuses more on his moral dilemmas, the consequences of his actions, the clash of ideologies between the characters, etc. while chess is mostly used as a metaphor. Lelouch also makes his fair share of mistakes because he's driven by his emotions, he's a much more complex and human character than Light, who thinks and acts like a machine with no feelings. Death Note is great but it's very different from Code Geass in a lot of aspects.