Currently, when the workflow writes into the notes, it is written in the contact record itself. However, we have clients who have MULTIPLE opportunities per contact, so a mixed bag of notes from many opportunities is a bit confusing for them.

It will be huge help if the note written on the opportunity will be displayed in that particular opportunity only. Even if the notes get mixed up in the contact record, that's alright as long as notes written in the opportunity STAYS in that specific opportunity.