Or, if you actually like being challenged, just get XTM. It's actually harder than vanilla.
I played X3 Reunion completely unmodded first, to see what it was like before getting the X-tended Mod. Your starting Buster is an M4(standard fighter versus light(M5) or heavy (M3) with more than ample firepower for, with excellent flying skills, taking down pirate, xenon and khak invaders. If you do combat skillfully, contrary to Apricotslice's claim(nothing against the guy, but he basically wants to be some galactic hero flying around in a super ship) you can really kick ass in your starting ship. I was dropping M5's and M4's in groups of three and four until I captured a pirate version Buster that was faster and had more firepower at the cost of a third of it's shielding. At this point, I switched ships, sold my original, and started dropping M3's in groups of 3 and 4. I did die occasionally, but that's what the save function is for.
Between capping pirates, the odd trade of opportunity, and doing missions, you can make enough money for your first ore mine in several hours time. If you read the conveniently available community made guide to X3, it's not at all overly complicated.
Is it deep? Can you play a long game? Yes. No one would find it interesting if you could simply start the game with the best ship you'll be able to get(oh look, X Rebirth!) and just curb stomp the enemy pilots like they're part of a swarm you fight against as you run through a level to get to the boss. You're not playing levels that get successively harder. You're living in an open universe.
If you run through the campaign, you're set up to build a nice little empire by the end of it. You'll have excellent credentials with the Argon and be well on your way to being a major economic power with your own mines and trade ships. Care for the empire well, and you can make a couple million an hour.