I'm not sure what you mean about the GEDCOM exporter being broken. You have two options for downloading a GEDCOM:
1) Download everyone in your Watchlist. This one has nothing to do with generations as it just includes everyone, whether or not you're even related. It will also include immediate family of those people, even if they aren't on your Watchlist, but with only basic information.
2) Download the tree starting with a person whose ID you specify. That one includes the direct ancestors (and their siblings I think) of the specified person, with a limit on the number of generations and the number of individuals, regardless of whether they're on your Watchlist. The limit is intentional, not a bug.