One great 'oc x sabe fanfic' could be 'The Unlikely Bond'. It beautifully portrays the relationship between the original character (oc) and Sabe. The story focuses on how they meet in a rather unexpected situation and then how their bond grows over time.
First, you need to develop your oc. Decide on their personality, backstory, and what makes them unique. For example, if your oc is a brave warrior, think about what led them to become so. Then, consider how they will interact with Sabe. Maybe they meet in a battle or in a diplomatic setting.
Maybe it's some kind of creative or humorous concept where the sexy woman is delivering pizza or having an adventure related to it. But it's quite an odd pairing.
I think the theme of 'Little Green Leaf' could potentially be about friendship and adventure. Maybe the little leaf makes friends with other elements in the cartoon and goes on exciting adventures together.
The cartoon might be bad because it lacks creativity, has inconsistent plot development, or fails to engage viewers effectively. Maybe the voice acting or sound effects are not up to the mark either.