The phrase "most thought" can be replaced with various synonyms depending on the context of the sentence. "Most considered" can be used when talking about something that has been carefully thought about or contemplated. "Most pondered" can be a suitable replacement when describing an idea that has been deeply reflected upon. "Most debated" can be used in a situation where people have been discussing a topic at length to come to a conclusion. "Most contemplated" can also be used to signify that an idea has been carefully examined and considered. Overall, using these synonyms can add more depth and variety to one's writing or speech.