Bioware left 0 room for additional ship docks in both the imperial and republic fleets. This game won't ever see additional classes added. AC's maybe, but not brand new classes.
That ship dock has been changed three times since I started testing beta 6-7 months ago.
It is not difficult for the devs to change entire areas of the game, it just takes time. Given the proper resources and tools, it probably wouldnt even take that long - I've been doing 3d modelling for years now and it'd probably take me a few hours to turn the current 4-way docking area into a 5 way docking area to fit an extra ship.
Anyways, I do not think imperial troopers will be added. If you're really wanting to play something akin to a soldier on the imperial side, I suggest rolling a Sniper. At level 29, if you have a VIP pass, you can get a set of imperial soldier's armor from the VIP section of vaiken spacedock.