The Dreamhost Control Panel is entirely different from cPanel. While I find it to be much more powerful and flexible, users who are only experienced with cPanel seem to have varying degrees of difficulty adapting to it. Generally, those with good technical understanding of webhosting in general, and nix operating systems in particular, have almost no trouble quickly adapting, and are invariably *thrilled with the added power! Others often take a while to "find their way around" but, once they understand how it works and where to go to accomplish their needs, they prefer it to cPanel.
Dreamhost does have a "web-based" ftp that provides you a way to upload in the circumstances you describe, but as it is a PHP based program, it can only upload files that are a maximum size of 8 MB. You can install other scripts on your webspace (such as perl-based file-managers, uploaders, etc) to provide a work-around for this limitation if you desire.