I also didn't play Freespace or the sequel back in the day. Only much later did I check it out, and while it has a good simulation element, I lose interest 5 or 6 missions into the game. I think the problem for me is that the very first space simulators I played where X-Wing and TIE-Fighter, which are so good at so many different levels, other space sims have always paled in comparison.
On one extreme we had Wing Commander, which had an excellent plot and storytelling, but the simulation element just plain sucked. On the other extreme there are the likes of Freespace, which have a great simulation element, but the rest of the game feels shallow and abandoned. X-Wing and TIE Fighter just got both sides right and then even put the incredibly sophisticated missions on top, and TIE Fighter just went above and beyond by adding the secret objectives and more poweful targeting controls, making it almost the perfect space simulator.
After TIE Fighter, you just can't go back anymore.