In our company, Designers do not own the project or the proof. They are only working with the Project Manager who provides all the direction and information on the proof and therefore need to be able to manipulate the comments so that the designers don't have to read through all the back and forth, and can find exactly what they need quickly and easily.
For clarity between roles, it seems to me a good idea to give different roles different flags that can be customized to the way they work. In that vein, I would like the Designers to use the Flag to indicate that the comment is either done or has more questions so they can easily track which comments they are working on.
However, the commenters need more ability to mark their comments to indicate things to the designers that they need to point out. I'd like to be able to use the Checkmark in that way but it's not customizable beyond Resolved. I would like that check to also have the ability to say "Ignore," for example (so they don't have to delete a comment) or "Read First" to indicate that this comment is going to change the entire page design as opposed to a minor change. The project managers could use the Flag but that would violate the rule that the Designers "own" the flag and also make training everyone harder, so that they can easily stick to a consistent way to use the flags.