Epcot was the start of the indoor queue...Its sort of the only one that always did (save SE)...
Im trying to recall opening day/early days attractions that had an indoor queue for MK and can only think of Country Bears, If You Had Wings, Fantasyland Theater, Pirates and Space Mountain...
Epcot was all indoor except SE.
Studios had GMR and Muppets inside, but everything else outside.
For some reason I read through my list and realize that Epcot seems to be the one that generated the indoor queue fallacy for WDW...Unique again, but the pavilion designs were meant to be inclusive of all aspects of the theme, so an outdoor queue would not make sense for any of those.