I like Le Cellier but honestly I think it's so popular because it is the least exotic restuarant over in World Showcase. Not everyone likes all the options at the other country's restuarants.
You have Mexico, Norway, China, Japan, Germany, America (no sit down restuarant) Itlay (allright so Italian might be on the list of what Americans think is normal), Morroco, France, and the UK (yes English food can be exotic or at least a little strange).
But then there is Canada...Le Cellier has cheese soup, steak, chicken, fish...it has food like any other nice American steakhouse chain restaurant with a little nicer atmosphere.
Don't get me wrong, I think Le Cellier has great food. But I think it might be at the top of everyone's list because it can satisfy even the pickiest and least adventurous of eaters in a "world" of exotic cuisine. Although if some of those picky eaters would look past the names they would find options like Lemon Chicken in Morocco and Macaroni and Cheese in France.