Suppose you are architecting a new web application, and you find that the requirements of your user interface make a classically thin-client HTML application a bit scary. You can't have the GUI controls you want, it looks like page refreshes will happen all over the place, and so on. Suppose I tell you that you should use Flash MX, since it allows you to construct an arbitrarily rich UI, the player is sufficiently ubiquitous (a category that suddenly admits to degrees!) for you to remain as cross-platform as you need to be, and you can call all of your EJBs from Flash just like you were writing a JSP. What would you say to me? I am impressed by the little bit that I've seen of Flash MX so far, and I'm looking for the arguments against it.