Thank you for the suggestions - I will forward the first one to the proper authorities to be considered further.
Concerning the second - indeed this can facilitate the development to some extent (adding separate assemblies to be compiled by Visual Studio and expose IntelliSense for them) and that is what we done for the Classic versions of RadControls for ASP.NET. However, this would bring unnecessary implications to the scripts/skins registration and make the deployment process cumbersome. That is why we decided that the optimal choice would be to have a single assembly for our controls.
the Telerik team