Well, as I said, JonusC is working on other templates that probably fit what you are looking for, as I understand it.
At present, it is the default Modern template and it's accompanying functionality versatilities that is the only option.
I am not sure if there is a Commenting component that works as you are suggesting though. I have the Azrul one installed on another site I have, and that too has the comment form open in the same fashion. I am not sure if it has a closed option.
But if you know how to make these templates you can probably fix a system to do this. I don't know how. Sorry.