The key here is that you are discussing an option that deals with low cost shared hosting and management of the server through the dreamhost panel.
If in fact you have a VPS or dedicated server it’s possible to turn off dreamhost management (panel functions) and set things up more precisely to your likes or needs. If you wish to stay with shared hosting, you could come up with some custom scripts that run on a periodic basis through cron to ‘publish’ new files submitted by a different user. (basically one user “logging in” to another on the same machine, and pulling files over.) This would be a server side solution.
For a local based solution, there are also options available to you. For example: I have winscp set up on a local machine in a mode that “watches” for changes to local files in a certain directory structure, when a file changes it is automatically SFTP’d to the server immediately. I could expand this on my local network by giving access to different users on the local network to various “folders” or directories within that structure being “watched” by winscp, when a user moved a new or changed a file within the “folder”, winscp would then immediately upload the file. The key here being that winscp knows the credentials to the website, other users don’t need them, they just need access to the folder or directory that winscp is watching. If this was the only method any user could use to publish a change to a file on the server, then you would also have the added benefit of always having an accurate local backup of the entire website at any given time.
The change dreamhost made (or is making) is in fact a necessary one for a shared hosting environment. It helps not only to prevent one shared account that has been compromised from the outside from potentially being used to compromise other accounts on the same server, but it also helps protect your site from other dreamhost users on the same machine. While we would like to think that other dreamhost customers sharing our shared servers would all respect our privacy and stay out of our stuff, they might just be there to do exactly that… find out what information they can gather about other sites sharing the same machine to hack or compromise the site either from inside or from outside using information gained by being able to other users stuff.