They need to take the worthless "Write a java app, we'll output in ajax for you!" ones of the list. They're the wrong way to solve the problem. The web isn't a desktop app, you'll never get anywhere trying to treat it like one.
I feel like many of the uses of "RIA" technologies (Java, Flex/Flash, Silverlight) are superfluous bling. Hell, a Flex app is all ActionScript anyway, why bother moving from one ECMAscript implementation to another when the one works fine natively in the browser, and the other requires a client download?
ExtJS is pretty good, but it's not as awesome as it might appear at first. As soon as you try to step outside the its features you're in for some adventures. For example IIRC there is no way to reorder tabs.
Thanks.