The permissions around Notes should be more granular, and allow to user to be able to edit the notes he created only.
The edit Notes permission is useful as it allows the user to correct any mistakes or add information as needed. However, with this same permission, one is able to change Notes from other users. The function that re-assigns the Note to the user who edited it last seems clever, but in reality, it's a terrible one as it loses the context of the first writer.
Example, we had a situation where the Head of Department left a comment of approval on a Deal, and by mistake it got edited by a Sales person. Now the comment of approval is seen as posted by the Sales person instead, changing the whole context of the Deal.
Again, the edit is useful, but one should be able to edit his/her own comments, and not that of others.