Holy shit! Cant belive I missed that this was coming out! Found it on vgpro.com downloading now. Thanks for informing me (Or maybe I should stab you in the eye as I have an important test tomorrow).
The Tau certainly have a much more tactical element to the use of their units, which I love. It's a crying shame that this wasn't used from the beginning with the other races.
As it stands the game is still very much geared towards amassing a larger army than your enemy and then rushing him. A great example is the second mission in the demo. The Space Marines, who by definition are supposed to be small but mighty forces, send wave after wave of men and dreadnoughts to their destruction when they are supposed to be holding the area and waiting for you to attack them, rediculous!
If that is even possible, Relic have probubly learned a lesson since their first DoW demo. There are likely no models for the units that are not accessible.
I loved the one vehicle the tau could get in the demo though...
From the demo I get the impression though that the world campaign will not be what I expected (40k: Total War).
Also what Xune said, its a shame the AI simply kept sending wave after wave of troops at your base, when they are meant to be one the defencive D: Shame problems like that aren't likely to be solved
This could well be the expansion that inspires me to buy the game. The Tau were ALWAYS (since 2001 :cheese my favourite race. Followed by the Tyranids. Here's hoping they're in expansion 3 eh?