Always gotta leave room for expansion, they are being pretty ambitious for a company of their size to begin with, so I would rather see them release "most" of the factions, including the primary players (Imperial Navy/Chaos/Orks) before they release Space Marines, Tau, Dirty Necrons....
the Tau are the 'youngest' of the races, I wouldn't expect to see them before the majority of the other races. Though, they are somewhat more popular than -some- of the others
As much as I love my Blueberries, nothing compares to the glory that Orks should be. Considering how sweet the gameplay vid looked, I expect brutal, brutal and loud guns firing at 'umies in the dead of space. Plus there are only two speeds for Orks, Shooty and Rammy
The only thing I don't like that I've seen so far have been the weapon effects; they just don't seem to have any weight, or 'oomph' to them; just some flashy lights in most cases.
Seeing as we are still about 6-9 months off from release, I imagine they will be added later.... indeed if you watch the trailer closely you see parts of the ships fall off, but don't stay missing >.>
All bow down to the imperial navy.... we shall conquer you xenos scum, traitorous rot, and savage mutant with our powerful weapons