To be fair, I think the confusion is mainly a side-effect of the slew of 'standalone expansions' (/bites back aspersions re: flagrant franchise-milking) that were trotted out, but the 'all expansions' wording on the ultimate edition page is a tad ambiguous.
While you're there, would it be feasible either to clarify or reconsider what one of the optional components installs? 'Multiplayer Scenerios' [sic] includes the exports\*.sg files for single-player one-off scenario games - without the component, trying to start a new single-player scenario results in an empty dialog. Worse, since the tutorial is implemented as a single-player scenario, this also means the 'Tutorial' button on the title screen is non-functional if the scenarios aren't installed.
As far as I can tell, this is an issue only if someone doesn't install that component, but it doesn't do wonders for the old first impressions. Given the component's only 100-odd meg versus the gig and a bit of obligatory files, the cleanest solution might be just to roll it into the main installation; if that's not easily done, I'd suggest at least putting a note in the component description to the effect that it includes bits of the single-player game.