where does it say it doesn't support the middle button? It's technically a multi-touch pad on top so it could detect when you want a middle mouse button click. It could technically detect 5 buttons on top of the mouse...

Also, back in the old linux days when most PCs only had 2 mouse buttons, people could click with both buttons to emulate the middle button. This was a standard option in the xfree86.config file. I would imagine something like this would be possible if the mouse can detect 5 independent touches on the pad.

Deal breaker for me is the lack of a clickly scroll wheel.

and scrolling documents and adding another axis of manipulation in apps (like google earth), and bunches of other things.