The nitpicks are:
The color. It's a bit off. It's not as bad as I thought. I was expecting a very brown, rusty color like in the sample pics Hasbro showed. It's not like that at all. Then again, the barge in the film isn't that brown, either. It still seems a little too dark/dull and not quite brown enough, but it's not as bad as I initially thought.
Even with the panels removed, the interior looks pretty dark most of the time. You have to get up in there to really appreciate how detailed and complex the interior is. Perhaps tiny LED lights would be the way to go?
Jabba's dais isn't removable. I'm not surprised by this at all, but it would have been nice, since Jabba's party room will get crowded quite easily.
The Ithorian skeleton isn't removable, either, which is a disappointment, though not a huge one.
The door to the prison doesn't open very widely. Or at least it won't on mine. Which makes the separate chains pretty useless, since you're meant to plug them into the wall of the prison, but there's just no way to get to those wall plugs (or do much with the prison at all) with the door the way it is. Unless mine just isn't working properly. It took me forever to get the door to slide at all, so it could be just me.
There are two rail guns which you can place in six different holes at various points along the rail. When trying to insert it into the rail at the stern, one piece of the rail popped up and off. It took me a little effort to squeeze it back down and now you can see the seam pretty well (as there is now a white spot where the two pieces come together.)
Though I'm not super annoyed by this, some of the corners of my box were crunched a bit. Since I intend to sell my box, this could impact the resale value. I know some weirdos like to keep things in their boxes, so they might find that disappointing.
TWO separate pieces were broken out of the box. The window flap on the port side that is on one of the large removable panels had one of its little hinges broken. And the cover piece for the cockpit has a crack in it. I'm going to contact Hasbro and hope for replacement parts.
I found the panels rather difficult to remove. I intend to keep them off for display purposes for the time being, but that worries me a bit. Doesn't seem to come off and on easily at all.
I can't get the tiny "antennae" pieces on the front to go in flush all the way. Similarly, there are three very tiny pieces that affix to the bottom of the stern that were very hard to get into their little holes. Those are so small that they add almost nothing to the barge in terms of aesthetics anyway.
Whew. That's a lot, but you asked for the nitpicks. And they really are nitpicks. For the most part, this thing rules!
The sails are awesome, but take a while to put together. They are easily removable for ease of play, though.
Below are a few pics: