Yes, this would be great.

If you have a Dolphin license, you can still download the moxymanager (older version now) from the Boonex site. You don't need the module, you can just manually install it in TinyMCE on your Cheetah site.

I have been planning on adding responsive file manager. I had added it to a Dolphin site once. https://www.responsivefilemanager.com You might want to take a look at it. I added the Moxymanager to a Dolphin site but I never really cared for it. You should also be able to add the quick upload justboil.me; it is out of development but I think it will still work.

That is because the tinymce editor does not have a built in file manager. They have a separate addon called moxymanager that they sell as an enhancement. Boonex had purchased a license for it at one point and provided it with dolphin however i believe the one boonex provided has expired.

Anyhow. I do plan on building a file manager for the editor. It's on my todo list. https://github.com/CheetahWSB/Cheetah/issues/77