Simply put, I suck at space shooters. So I'm wondering how much of this plays like a traditional space shooter, and how much of it plays like the advertised 'economic sim'?

The economic part of the game is basic at most. You simply just buy cheap, jump next door (pretty much to the closest system) and sell high. The products arn't exactly diverse, and it feels a little tacked on.
The focus in Darkstar One is really arcade style combat, but don't be put off by that as you can leave it on the easiest difficulty. The combat is simple enough to enjoy and it wont be drawn out because you can get a lot of damage down.
Trading is basic, and you only need to really do it at the start of the game for cash.

This is definitely a shooter. If you are not good at shooters and still want to play the game make sure you upgrade your hull early and often to get turrets as soon as possible. They auto-aim and auto-fire, and once you have a couple they basically do all of the work for you.