The friction is only destructive if you enter the atmosphere too fast. The reason current spacecraft need heat shields is because they have no way to drop 15,000 mph worth of velocity before they touch air because of limited fuel. Presumably, the ships of star wars can slow down as much as they want, they seem to have all the delta-v they need for maneuvering. An SD could theoretically slow to a hundred miles per hour and come down to land at its leisure if it had repulsorlifts or big wings to keep it flying. But, since that model apparently doesn't, there's an apparent discrepency. If that ship is in orbit, it shouldn't look that big. If it's in the atmosphere, it should either be falling or somehow using the wedge shape as a lifting surface, but since it's supposedly not designed for atmospheric flight, that would seem difficult.
(who am I kidding, I have no way of turning off nerdmode. )