I have never been one to think that the mouse form factor that we all know and love needs a complete redesign. I will agree some mice are more comfortable to use than others are, but I like the traditional style myself. Just give me lots of sensitivity and I am good.
If you want to try a different style mouse altogether the Jelfin ball-shaped mouse may be worth a look. The mouse is round and is covered with a gel coating for ergonomics and a comfortable feel. The ball shape of the mouse promises to fit the curve of your hand perfectly.
The mouse is designed to be sort of like a stress ball that can be touched and squeezed. The ball mouse comes in blue, red, yellow, green, and pink colors. The mouse also ships in a can that acts as a transportation container. Sensitivity for the mouse is 1000 dpi and it is available now for $34.95.