Yeah thats kinda my thinking. We maintain a database of all of the free Win32 software on SourceForge and try to get them all to use MSI or NSIS to package them.
I think that we should also support "plain old zip files" as a package type (or a zip file with a little info about what to do). A large number of FOSS software packages dont need an installer at all, if all you have to do to get it to work is "unzip it into a folder", an installer is overkill.