This isn't directed at anyone in particular, but-
Currently, World Showcase is a mix of a few worthwhile attractions that are popular (including Frozen, sorry crybabies), a few cultural exhibits that literally nobody bothers to look at, and shopping/dining/performers which currently happens to be the main draw of the area. This isn't any different from the day EPCOT opened though.
Mexico- Mid level ride, medium popularity, Performers/Shopping/Dining/Architecture are the real draw, the ride isn't even noticed by most
Norway- Mid level ride, extreme popularity (now), cultural area that nobody cares for
China- Circlevision, non-existent culture currently in museum, both are largely ignored in favor Performers/Shopping/Dining/Architecture
Germany- Performers/Shopping/Dining/Architecture are the only real draw
Italy- Performers/Shopping/Dining/Architecture are the only real draw
USA- Major show performed, small museum that's mildly popular
Japan- Small museum which is ignored, Performers/Shopping/Dining/Architecture are the only real draw
Morocco - Small museum which is ignored, Performers/Shopping/Dining/Architecture are the only real draw
France- Minor film which is ignored, - Performers/Shopping/Dining/Architecture are the only real draw
UK- Performers/Shopping/Dining/Architecture are the only real draw
Canada- Circlevision mostly ignored, Performers/Shopping/Dining/Architecture are the only real draw
So right now, half of the pavilions have no real draw beyond Performers/Shopping/Dining/Architecture, and the remaining half don't actually draw people in search of attractions except for the USA, Norway and a small percentage of people who sit through the films. Sorry guys, it's always been about the Performers/Shopping/Dining/Architecture- not rides or other attractions. While I'd love to see more "real" attractions, it's not some travesty if another pavilion were to open offering only Performers/Shopping/Dining/Architecture. That would simply reflect the offerings that are largely present at all of the current counties save for a few. That hasn't really changed. I get that every country had some form of ride/attraction that was axed along the way (Meet the World, Mt Fuji, Shinkansen walk through and others just for Japan!), but none of that actually came to fruition. What's there now is largely what was there when the area opened.
American Adventure is literally the only headliner in the World Showcase aside from Frozen. I certainly hope that there's a headliner attraction in any new country, but that would in fact be a departure from the makeup of the showcase as it is now.
Sometimes I think people forget that the Performers/Shopping/Dining/Architecture function as the attraction for World Showcase. Well, that and booze.