Yes, in some areas Silverlight has a lot of catching up to do :). I have spent some time doing flash/flex and understand very well what you mean. Animations can add "coolness" to an app if they are used appropriately.
I have always advocated the idea that a technology should be used for its strengths and not just for the sake of a technology.
Silverlight allows us to customize a lot of things but unfortunately Storyboards (Animations) are not one of them. The problem you have to sacrifice something if you need to make really good customizable animations.
If a designer cannot modify them, its no good. If they are performing poorly, its no good. If they are hard to use, it is no good. Internally, we have some ideas about how really good animations can be made (and our UI people have some ideas too :)) but it is always hard to tell how far should we go with them. We will definitely add animations and make them usable.
Take a look at the calendar for example, it has 20+ properties for DataTempalte, TemplateSelectors, Styles, StyleSelectors and Panels (and we are not counting the format and visibility properties). Currently there are some animations but you cannot edit them. I do not like that! And yes, we are looking for ways to make them customizable and easy to use. (And we are getting there).
Thanks for sharing your thoughts and experience on the subject! It allows us to focus on the important things for you, and in the end, this is what matters.
the Telerik team