It's huge, but no. It's still too small I think, which this
picture illustrates (though not very well, you'll have to take my word on it :P ).
My 12 m long fighter can barelly fit into the secondary docking bay. The Lambda shuttle is, what, twice as long? Atleast.
But that's nothing new from any of the previous space sims either.
So I didn't have high hopes this game would get the scale right either.
That being said though, it could just be a miss scaling of the docking bay(s). Haven't taken measurements of the full lenght of the star destroyer.