Rat ride will be a decent addition.
Rode the Paris version last week and enjoyed it, didn't blow me away but it was fun. It is screen heavy but it works, I couldn't imagine a way of doing it without the screens to be honest. The trackless RVs are neat, the programming to get them interacting and being where they need to be by a certain time is nothing short of incredible, was watching them just as much as the ride on my second go. Can't comment on the queue as did single rider.
The whole area around the ride is really well done, Ratatouille (I hate to say it) will fit really well into the existing Epcot pavilion, it is a true Disney ride which will be loved by the fans.
@AliciaStella , yes there was a restaurant, adorned with over sized themeing bottles, cutlery, champagne corks as chairs and giant Christmas string lights etc etc, all to give the idea of us being as small as the rat. Looked pretty neat and the food was good, reminded me very much of a DCL restaurant.