TMatt, I don't know what planet you are on, but silverlight is BS. It was created to compete with Flash, but Flash is SOOO 10 years ago. Web Applications were around long before Silverlight. I dare you to compare any application built with Silverlight to one built a more modern and acceptable approach such as degradable HTML5.
Telerik doesn't necessarily stay on top of the current trends, but they do keep up with everything Microsoft. Earlier Telerik stuff only worked with IE for instance. While this isn't necessarily a bad thing, Silverlight is one MS solution that was unnecessary from its inception.
XAML is great for markup in dedicated environments since it is platform independent and gives dedicated applications the design ease of the HTML. Silverlight is XAML for the web -- WHY???
I have had multiple clients choose other CMS options over Sitefinity for this one reason... Silverlight is a dirty word for any non-dev, or any dev that didn't start as a winform develpoper for that matter.
I would like to see Silverlight removed completely...
1. ClientBin has to match exactly with Bin, which causes headaches
2. Even though Silverlight has OSX and Linux implementations they are wonky --
For instance if you drag a video control on a page, don't expect to work on anything but
windows. Even worse, most of the Silverlight controls in Sitefinity have to deal with
images and video. Image and Video folks, a.k.a Designers, a.k.a Apple Fan-Boys have no
idea what Silverlight is, causing headaches for the IT department.
3. There is absolutely no reason for Silverlight, there are plenty of JQuery multi-upload
tools out there as well as Video players that not only work everywhere but have added
functionality such as automatically choosing the best quality for the browser/screen.
4. Silverlight requires a second development environment
5. The world is Mobile -- Where is Silverlight and Flash in the mobile world !?!
P.S. 4.4 is looking great by the way, this is one of the last complaints I have with your system.