A few have commented that multicrew has little to offer traders or explorers, so I wanted to suggest a couple of possible uses for the gunner role. As described by the devs, this will give the cmdr using it more or less a 360 degree view outside, that can be used to target ships outside with turrets or missiles. This 360 degree view could also be useful for traders and explorers if different, non-offensive modes were added to it:
1. Focused shielding: the cmdr at the gunner's station controls the position of a shield "sweet spot" that is much stronger than the rest of the shield but is only about 10 degrees wide. The idea is that a trader or explorer can use that to more effectively deflect incoming fire like a warrior deflecting arrows. It would also benefit smaller ships that aren't as likely to use turrets but could use some extra defense.
2. Telescope: the commander at the gunner's station can zoom in the view (or a small part of it) to help when looking for interesting things in space or on the ground. It is important that this zooming be something that can be changed so that the observer can switch between scanning a wide area and a small one.