I like a good bit of trading myself and was a bit little sad as a new customer that it .... doesn't really seem to be a thing.
Totally understand why trading is an icky thing in a lot of games, where it essentially becomes rote repetition. Location A sells product 1, you carry it to Location B to trade it for product 2, then finally Location C and sell your product 2 for insane profits. Then you do it over again. The thing that makes systems like that terrible are lack of unpredictability... EV:Nova was absolutely terrible about this, where you could run the same freight loop a few times, hire a freighter, run the loop, hire a bigger freighter, run the loop, and then before you even start doing anything fun in the game you have oceans of cash that you didn't really earn. THAT should be avoided, yes. But Starsector already has concepts in place to prevent that, i.e. pirates and dynamic economies. Even the fact that in Starsector you have to pay for fuel and supplies acts as an informal trade tariff in its own right, since unlike most similar games we have to pay to move freight around
It seems like trading is a thing that could be in the game and not completely destroy the fun, so long as you're actually competing against other agents for the cargo and so long as the pirates become very interested in what you're up to. A massively profitable trade route should either be temporary (causing a scramble of activity when it opens) or very dangerous (known routes would be ambush bait). Would love to see the 30% trade tariffs reconsidered in light of the otherwise wildly unstable economy, as well as some new missions offered to players. Either one-off "courier this small valuable thing", or bulk freight where the base pay is really pathetic but we get a bonus by the ton for how much freight we arrive with. Or even sign on to a convoy, where we put in some money to help stock the convoy and everybody shares the profits at the end.
(shrug)
Since you mentioned EV:N, did you play before they nerfed the Opal run? I don't remember the name of the system but the idea was pretty simple. There were two planets in system, but very far apart (by EV:N standards). One had opals at a low price, one had them at a high price, so obviously stupid easy trade.
The one catch was that the system was always swarming with high quality large pirates (manticores and the like), so it was supposed to be a death sprint to see if you could manage to protect your fleet whilst running the blockage (rather than shift queue a few jumps and watching the animations play).
In practice you bought and afterburner, jetted around them, and broke the economy faster and harder than normal, first by trading opals for profit, then by trading lots of opals for profit, then by just pirating the pirate ships in the system (which quickly became worth more than the opals when you plundered and sold them), so they nerfed the whole thing.
While obviously demonstrating the flaws with bad trading systems, it shows the idea that I really wish starsector would try to capture. Trying to evade pirates (something you'd actually have to do in star sector compared to EV:N's watch me jump), smuggle cargo, and still turn a profit.
The exact same idea (highly profitable in system trade route with dangerous pirates everywhere) already works so much better in star sector just do to it's general design. There's an actual stealth mechanic, systems are much larger, fleets are much more dangerous, and there's a hell of a lot more interaction possible (although maybe not currently, map skills are mostly stealth or go faster) to trying to get past them.