I've set up several WordPress sites on my domains. Because of development needs, often I create these on a separate subdomain (or even a separate server, e.g. a local dev machine) and then transfer them to their final "home" on DreamHost when I am ready to launch the site.
The unfortunate consequence of that is that I now have a number of WP sites which are not recognized as such by the One-Click Installer. So I currently am going in to all the control panels by hand and updating the WordPress installs myself (3.5.1 was just released). That's not awful, but there are some great benefits to the unattended auto-upgrades that I could get with the One-Click Installer (customers don't need me to always have an admin account in their site, security updates can be released very quickly, etc.).
I know there are other (and commercial) options for this type of thing, but it would be really cool if DreamHost allowed you to "submit" a WordPress site that you had manually installed to the One-Click Installer, so that DH could take over the routine management stuff for you.