The economic system is fairly well thought-out, and I am surprised at the number of people who complain about problems making money. It may be that players are relying on the in-game import/export tools too much. These can be misleading because they operate on a system, but the economy actually varies by planet/station. (So in-system trade can be profitable, too.):
* Everybody needs food, clothing, and medicine. Rich economies want luxury items.
* Agricultural planets produce food items and need agricultural machinery. They also have at least some luxuries, usually beer.
* Industrial planets produce clothes, medicine, and machinery of various sorts, and need input materials such as metals, cloth, and semiconductors.
* Refining stations turn minerals into metals and other inputs.
* Extraction stations industries produce minerals.
* High-tech planets produce luxuries, automation items for all the above, and need computers and input materials. They also produce weapons.
* There are some niche/specialized economies I haven't yet fully explored: "Imperial", terraforming, service, tourism. Also some planets have a blended economy.
It's not hard to set up loops of various sizes:
Agricultural <-> Industrial works well
Extraction -> Refining -> Industrial -> Extraction is a little trickier because not all ores are refined at all stations, but you can easily learn what works (and their trade diagram has gotten better at indicating what minerals exist where.)
Agricultural -> Industrial -> High Tech -> Agriculture works well with a rich agricultural world. Can substitute in Refining instead of Industrial.
Some of the gamma players seem to really not know what to do with themselves in a truly open world. There's not a plot to hop back onto when you're tired of the side quests. However, the political simulation (factions get influence based on user input) provides the seeds of good endgame play, and can provide near-term goals for starting players too.
The final complaint I don't really get is that the game is "incomplete" without the ability to land on planets (which was part of "Frontier"). I can totally understand why that got cut as a release feature, and I don't understand why players are so attached to it--- it provides some more landscape but there is plenty to go explore without actually visiting the surface. If this feature were present, it wouldn't add to the gameplay in any way.
The thing I think is most likely to cause problems is that any of the "evil" options are so heavily punished that players can't even try them out. Piracy or assassination or just being caught with salvaged ("stolen") or smuggled goods puts you on a downward slope with the local government, and it seems very hard to get back into their good graces. (ED doesn't have alternate characters either to let users explore different ways to play.) This is fine from a simulationist perspective, but from a player perspective it can feel like those options are locked off. On the other hand, I think this is something where paying attention to the faction system and local politics can really pay off. If you go pirate in an independent system, the Federation doesn't care.
Compared to "Frontier", combat is a lot more fun and varied. Frontier sacrificed playability for adherence to Newtonian physics. Elite: Dangerous gives you enough control to do some fancy maneuvering, but puts a speed limit in place so you don't just whip by your opponent at high speed. There are also a bunch of customization options and different sorts of weapon systems to try out.
Overall, the game looks good, plays pretty well, and is a quite fun update for anybody who liked the original Elite (or even Frontier.)