I am sure it is something I will get used to but I could change pen colour in one click with the radial menu. It is at least two clicks to change the colour in the tab interface. One to drop down the colour tablet and then one to select the colour. That is assuming I am already on the pen tab. If not then it is three clicks. Based on that I am not sure how you can say it is the same or less clicks. Now I am no expert so if there is some short cut I am missing please set me straight.
As for the use with a mouse I am not sure how people struggled with the radial menu. A mouse is more precise so I am not sure why people struggled.
I understand that we inkers are in the minority but as MS has already developed the UI it would be pretty easy to make it an option that people can turn on and off.
Thanks for sharing you view point. It is appreciated.