I'm not ready to trade my mouse in just yet. How do the ergonomics compare? How well will it work for FPS gaming? Can I rest my forefinger on the surface without clicking? How about the scroll wheel? Part of knowing where that is (for me) is by feel. Tactile feedback?
What are the REAL advantages of this over a mouse for general purpose use? Is it cheaper? Easier to use? More ergonomic? More responsive? More predictable response? Exactly what problem is it trying to solve that the mouse does not? To replace the mouse it must be more convenient, cheaper, or both. It can't be less convenient and can't be much more expensive. It must be at least as reliable, but greater reliability won't be enough to sell it by itself. If it's less responsive you'll lose the gaming crowd, a lot of them won't even use wireless mice. (So the pickup interpretation had better be damned fast.) Same with precision; more won't help much, less will hurt.
Left-handed? Well, he already suggested that it could be detachable. Some of us prefer mice... and frankly, I don't think the trackpad will work well for first-person-shooter gaming. :)
So if it's detachable, make it symmetrical; it can plug in the left side or the right. Gives you a spare USB connection, too. Bonus!
The Mouse Will Be Dead by 2019
Behold, the Revolutionary Apple Wireless Touchboard Concept