well,
a) The ship isn't new, it was the pre-release content. It was already made long ago.
b) It doesn't take all people on the team to all concentrate on the same problems, there is also room for further development. You can't - for example - work with two people at once on the same pc working out the same problem at the same time with the same tool. And not all the developers have the same task/speciality either, etc.
c) other customers WANT new ships, an editor, etc..
Thats a few possible answers for you. But the problems are being worked on.. They are not ignored in favour of new content, it just works side by side.
Regards,
Fred