Hey! Yes, I can give you a breakdown of our thought process here.
It looks like a learner suggested we add “thought” to the our allow list since it’s used in the mnemonic for 回想, and this sparked a conversation about the meanings of 想.
Because 考え is a definition/synonym for 想 in some dictionaries, we considered “thought” to be a good choice to add to the kanji’s meanings. However, 想 is more associated with the words “imagine” or “think,” and “concept” didn’t stand out as much when we reevaluated 想. Also, only the subject 回想 uses “thought” in the mnemonic. Since we didn’t have any other kanji that use “imagine” as a primary meaning, we thought “imagine” could be a good candidate.
So in the end we chose to add “imagine” as the primary meaning, “contemplate” as the alternate meaning, and moved “concept" to the allow list, along with “imagining,” “think,” “thinking,” “thought,” and “contemplation."