1. Story - Great setting. Great premise for interesting conflict. Give me a good coherent story. Make me care about why I'm blowing things up and I'll keep killing 5 squadrons of ships for a while. Take it from a former commercial text-based game developer... story helps.
2. Open Exploration - I want to beam down to a planet and be able to explore it. I know this may not be possible for all the randomly generated planets, but I would like to see some planets where I don't feel like I'm walking around in a box or an oval. I'm a strong Explorer on the Bartle scale.
3. Community - Social areas need more of a purpose.