The Disney ship's are actually 83,000. This is a very popular size. Not to big, but not too large. The Disney ships came out in 1998 and 1999. With the mega ships being built now days well over 100,000 and soon to be over 200,000; then the 83,000 may seem small. I don't think that should affect how smooth the ride though. I just sailed on the NCL Sky at 77,104 and it was as smooth as glass.
Disney isn't for everybody though. They are a different experience. It's great there are so many cruise lines to choose from.