Note: I realize this is based off of the Minecraft Installer, but it was the first that came to mind.
Main Window: Shows latest news from the Dwarf Fortress development thread at bay12games.com/dwarves, as well as providing a link to the donations page (Donations would open in the default browser).
Play: Initializes the .exe file for Dwarf Fortress of the currently selected profile.
Profile (Bottom Tab): Redirects 'play' across various folders. By default there are 2 for each of the most stable version in a cycle. The first is the Vanilla version, while the second is where minor mods are automatically downloaded to (by default).
Profile (Upper Tabs): Manages profiles selectable within the bottom tab and allows a person to select which utilities launch when a certain profile is selected, as well as determining where minor mods are downloaded.
Major Mods: Allows user to download total conversions and the other mods that modify the default raws. Rather than overlay onto an existing version, a new profile is made. If it has its own launcher, that would be launched rather than the default DF executable.
Minor Mods: Allows user to download mods that add content, but do not modify existing raw files. Downloading these puts them in the raws of a version compatible with the cycle they were released in. Profiles (upper tab) can allow them to be downloaded into total conversion profiles.
Utilities: Allows user to download utilities to a compatible profile. Profiles (upper tab) determines where they are downloaded to, and whether to initialize them on the start of a game using that profile.
Graphics: Allows user to download graphics packs to a compatible profile. Graphics, like Total Conversions, would go into their own profile due to modifying several files.
Major Mods, Minor Mods, Utilities, and Graphics would all refer to DFFD for the downloads. A decompression programs would need to be integrated so as to unpackage the zipped files. Each of those tabs would list popular mods/utilities/graphics packs, as well as providing a randomized (Mod/Utility/Graphics Pack) of the Day, and a recently updated list. Might want to rename 'Major Mods' to something like 'New Profiles', so that stuff like DFhack would fit under it, since that modifies major files rather than being something that could be turned on and off, and 'Minor Mods' could be renamed to 'Addons', since that is more what they are in this system.
I don't know how much effort would be required, but that is offset by not having the utility need to be updated every time a new version comes out, since all it would do is call the .exe file to run, and providing a convenience for downloading mods, utilities, and graphics packs, making people more likely to try out a few since they don't have to be manually installed.
Anyway, that's the idea. What do you think?