I have tried the ship designer too (obviously, it's fun), but I also have the problem of not being able to design what I have in my mind. Similarly, I have no drawing skills (I can picture many things in my mind, but none of them accurately make it to paper).
One of the problems is that I get overwhelmed in the many different parts. They're all numbered, ok, but that's just about all the information you have. If you want to add an antenna to something, it's fairly easy (there are only two or three of them and they're recognizable), but if you want that one specific piece of hull to add to the ship, to make it look wider, or higher, then there's a chance you're looking for it for it for a long time, because you can't see it in the large group of them but when you add it, you find out that it doesn't look right after all or that it actually wasn't the hull part you were looking for.
My proposed solution to this would be to add a new type of sorting, next to the option of sorting on size or on number (that thing is very useful if you want to change a design, so when you have a reference from the list of things that are already added to the ship). Have us sort on the ship "type". There can be a type for wings, engines and hull pieces. It makes searching for things a lot easier.
The other problem more likely has to do with the experience I have with the ship designer, although the user friendliness can be improved on more parts than just a new way to sort stuff (and it probably will, considering that this is the beta). Anyway, my plan is to make my own version of a star destroyer, because the biggest flaw I see with the Star Wars ones, is that they have obvious weak points and that the laser cannons are too small to be seen, while the lasers can do a lot of damage.
I'm not that far obviously (otherwise I wouldn't have made a post this long), but for now I'll have to settle with my own version of a blockade runner, with lots of laser guns and lots of engines (although for the game mechanics I should have gotten extra hyperdrives, a move radius of 8 is just not enough for something that's supposed to appear, blow a hole in a blockade and then cruise through it. More screenshots to follow: