I have been using Wacom tablets for 15 years in professional design software. I think it is important to remember that a tablet is another tool, not a mouse replacement. I can understand how some might see it as slower especially if they are trying to use it for menu navigation and rotation/zoom.
I have found that I use the mouse for my initial larger placement and automatic cuts then use my pen/tablet for my sculpting. I have preset tool settings for my sculpting and use the pressure sensitivity. I can mimic the surrounding dentition in any lobes and grooves in under a minute. In a simple single unit total design time is 5-6mins. I am using 3shape currently although we are trying out Cloudpoint right now also.