What we're doing with the invasion screen this time around is shifting the focus away from the soldiers and onto the planet's surface (what improvements that have been built)...so unfortunatly there'll be no soldiers to see.
However, as you build up your worlds, you'll get to see your sprawling cities in full glory (and get to see them burn to the ground if you're not prepared).

Like that.
However, when invasions get an overhaul for GC3 (sometime in the forseeable future) I'm sure you'll be seeing your soldiers in action.