The vastness of the universe in the original Elite had a wow factor, but really didn't serve much purpose in the game.
Much more important was the trading aspect.
Some systems were safe, and law abiding, and had police ships. Some were criminal, and had pirates circling. Many goods were common across them, but you could buy narcotics and slaves from criminal systems. Your behaviour affected how other ships would react - trading slaves was profitable, but you'd be attacked by police and pirates. Attacking other cargo ships (to capture their cargo) would turn you criminal. Attacking pirates would make you more law-abiding.
You could find two systems and find the right product to buy-low, sell-high.
There's more in common with games like Fallout 3, although fallout 3 didn't really have a good trading system.
(All the above is from memory. I have no doubt made mistakes.
There is one minor aspect of the game that deserves mentioning - the mildly brutal learning curve just to fly the ship. Do you remember the first time you tried to dock with a spinning station? And how the autopilot mocked you, priced at 10 times your net worth?
Docking was my favorite part of the game. Particularly when under fire and heavily damaged. How fast should I come in? How steep? Can't be too cautious or this pirate on my tail will waste me. Glance the edges and I'll be dead anyway.
<armchair role=gamedev>
There are other places in Elite where similar high pressure situations could be added. The obvious one is to make the sun scoop more dangerous. Make it work better the deeper you go in the sun. But in addition to the hard surface to avoid crashing into, the sun does damage over time proportionate to depth. (Maybe collection rate is linear to depth while damage is squared, with a small safe zone for the patient at the top.)
A less exciting one would be cargo transfer. What if cargo was moved by porters? The union guys take their time, but do a good job. You could do it yourself, but you'll get irate customers if you clip a corner and damage the stock. Better hurry though, the police inspections are only a few docking bays down the row from your ship.
Much more important was the trading aspect.
Some systems were safe, and law abiding, and had police ships. Some were criminal, and had pirates circling. Many goods were common across them, but you could buy narcotics and slaves from criminal systems. Your behaviour affected how other ships would react - trading slaves was profitable, but you'd be attacked by police and pirates. Attacking other cargo ships (to capture their cargo) would turn you criminal. Attacking pirates would make you more law-abiding.
You could find two systems and find the right product to buy-low, sell-high.
There's more in common with games like Fallout 3, although fallout 3 didn't really have a good trading system.
(All the above is from memory. I have no doubt made mistakes.